3x+1 Class records calculation progress map
Status of the 3x+1 class record progress as of: Aug 16, 2019.
Intervals are indicated in blocks of 100,000,000,000,000 (100 E+12 or 100 trillion numbers).
Calculation of a single block takes approximately 7 days of (idle) time on 2.4 GHz processor.

All class records found so far can be viewed on the class records page.
This project can only run because of many cooperating contributors.
If you would like to contribute one or more blocks please go to the search page.
Note : the 3x+1 problem is just one of many distributed projects on the internet.
Trajectory of 63,728,127
Progress history
July 11 2019 : All blocks up to 509,000 completed. One more class record confirmed.
May 12 2019 : All blocks up to 506,600 completed. One more class record confirmed.
May 5 2019 : All blocks up to 500,000 completed. Delay record 2264 and five more class records confirmed.
April 18 2019 : All blocks up to 479,400 completed.
April 5 2019 : All blocks up to 476,400 completed. Three more class records confirmed.
March 21 2019 : All blocks up to 455,200 completed. Lowest missing class record (2070) confirmed.
February 3 2019 : All blocks up to 435,300 completed. Two more class records confirmed.
January 15 2019 : All blocks up to 432,500 completed. Two more class records confirmed.
December 11 2018 : All blocks up to 416,800 completed. One more class record confirmed.
November 18 2018 : All blocks up to 413,000 completed. Six more class records confirmed.
November 2 2018 : All blocks up to 387,000 completed. Delay record 2261 and two more class records confirmed.
October 14 2018 : All blocks up to 366,400 completed. Six more class records confirmed.
Show/Hide earlier milestones
June 2018 : All blocks up to 346,000 completed. Three more class records confirmed.
December 2017 : All blocks up to 326,500 completed. Five more class records confirmed.
May 2017 : All blocks up to 305,400 completed. 258 reached. Two more class record confirmed.
October 2016 : All blocks up to 280,000 completed. Delay record 2258 and two more class records confirmed.
March 2016 : All blocks up to 275,200 completed. Four more class records confirmed.
March 19 2016 : Possible new Delay Record (Delay 2258) found by Lutz.
December 2015 : All blocks up to 263,350 completed. Four more class records confirmed. 2100 class records known.
July 2015 : All blocks up to 245,500 completed. Five more class records confirmed.
December 2014 : All blocks up to 222,280 completed. Three more class records confirmed.
November 2014 : All blocks up to 213,800 completed. Delay record 2255 and two more class records confirmed.
May 2014 : All blocks up to 203,920 completed. Three class records confirmed.
February 2014 : All blocks up to 194,060 completed. Five class records confirmed. All class records up to 2050 known.
November 2013 : All blocks up to 184,000 completed. Three more class records confirmed
June 2013 : All blocks up to 166,700 completed. Two more class records confirmed.
April 2013 : All blocks up to 165,200 completed. One more class record confirmed.
February 2013 : All blocks up to 160,740 completed. Six more class records confirmed.
November 2012 : All blocks up to 148,800 completed. Five more class records confirmed
May 2012 : All blocks up to 132,360 completed. Five class records confirmed.
January 2012 : All blocks up to 121,500 completed. Final missing class record below 2000 found.
December 2011 : All blocks up to 120,200 completed. One class record confirmed.
October 2011 : All blocks up to 117,000 completed. Three more class record confirmed.
July 2011 : All blocks up to 107,500 completed. Delay record 2254 and three class records confirmed.
April 2011 : All blocks up to 97,080 completed. Delay Record 2091 and two other class records confirmed.
November 2010 : All blocks up to 91,880 completed. Three class records confirmed.
August 2010 : All blocks up to 90,000 completed. Four more class records confirmed.
February 2010 : All blocks up to 82,700 completed. Two class records confirmed.
June 2009 : All blocks up to 76,160 completed. The lowest missing CR (1964) and one other confirmed.
April 2009 : All blocks up to 72,520 completed, passing 256. Three class records confirmed.
February 2009 : All blocks up to 71,020 completed. One more class record confirmed.
December 2008 : All blocks up to 69,740 completed. The lowest missing CR (1951) and two more confirmed.
November 2008 : All blocks up to 67,500 completed. Class record 2000 finally confirmed.
October 2008 : All blocks up to 66,380 completed. Four more class records confirmed.
May 2008 : All blocks up to 61,160 completed. The lowest missing CR (1925) and three others confirmed.
December 2007 : All blocks up to 58,600 completed. Four class records confirmed.
April 2007 : All blocks up to 54,540 completed. Five more class records confirmed.
October 2006 : All blocks up to 50,000 completed. Delay Record 2090 and five class records confirmed.
November 2005 : All blocks up to 46,100 completed. Double of Record 2045 confirmed as Delay Record 2046.
August 2005 : All blocks up to 45,040 completed. Five class records confirmed.
May 2005 : Delay Record of 2090 found at ±46,785 E+12 by Eric
February 2005 : All blocks up to 42,060 completed. Three more class record confirmed.
November 2004 : All blocks up to 40,000 completed. Four class records confirmed.
August 2004 : All blocks up to 37,500 completed. Another four class records confirmed.
May 2004 : All blocks up to 36,120 completed. Seven class records confirmed.
January 2004 : All blocks up to 31,960 completed. Five further class records confirmed.
November 2003 : All blocks up to 29,840 completed. One more class record confirmed.
August 2003 : All blocks up to 29,240 completed. Another fifteen class records confirmed.
April 2003 : All blocks up to 23,100 completed. Delay record 2045 and seven class records confirmed.
December 2002 : All blocks up to 20,100 completed. All class records below 1900 known.
November 2002 : All blocks up to 20,000 completed. Delay record 2042 and fourteen class records confirmed.
November 2002 : Delay Record of 2045 found at ±22,702 E+12 by Kevin
July 2002 : All blocks up to 16,460 completed. Delay record 2039 and fifteen class records confirmed.
April 2002 : All blocks up to 12,720 completed. Another fourteen class records confirmed.
March 2002 : Delay Record of 2042 found at ±17,026 E+12 by Michael
February 2002 : All blocks up to 9340 completed. Two more class records confirmed.
December 2001 : Delay Record of 2039 found at ±12,770 E+12 by Billy
November 2001 : All blocks up to 9020 completed. One Delay record and ten class records confirmed.
September 2001 : All blocks up to 6800 completed. Three Delay records and fourteen class records confirmed. 
August 2001 : All blocks up to 3600 completed. Two Delay records and five class records confirmed
June 2001 : Delay Record of 1958 found at ±7579 E+12 by Kevin
May 2001 : Delay Record of 1919 found at ±6482 E+12 by Kevin
April 2001 : Delay Record of 1916 found at ±4861 E+12 by Kevin
March 2001 : Delay Record of 1903 found at ±4320 E+12 by Kevin
March 2001 : Delay Record of 1895 found at ±3586 E+12 by Eric
March 2001 : Delay Record of 1874 found at ±2978 E+12 by Kevin
February 2001 : All blocks up to 2620 completed. Three class records confirmed.
January 2001 : New Class and Delay Record of 1871 found at 2234,047405,400065.

Range 2000-20000
completed (view)
Range 20000-40000
completed (view)
Range 40000-60000
completed (view)
Range 60000-80000
completed (view)
Range 80000-100000
completed (view)
Range 100000-120000
completed (view)
Range 120000-140000
completed (view)
Range 140000-160000
completed (view)
Range 160000-180000
completed (view)
Range 180000-200000
completed (view)
Range 200000-300000
completed (view)
Range 300000-400000
completed (view)
Range 400000-500000
completed (view)
 
Not yet assigned Assigned,
not yet started
Assigned,
in progress
Entire interval
completed
Interval completed
class record found
500000-100
Kevin
500100-200
Kevin
500200-300
Kevin
500300-400
Kevin
500400-500
Kevin
500500-600
Kevin
500600-700
Kevin
500700-800
Kevin
500800-900
Kevin
500900-000
Kevin
501000-100
Kevin
501100-200
Kevin
501200-300
Kevin
501300-400
Kevin
501400-500
Kevin
501500-600
Kevin
501600-700
Kevin
501700-800
Kevin
501800-900
Kevin
501900-000
Kevin
502000-100
Kevin
502100-200
Kevin
502200-300
Kevin
502300-400
Kevin
502400-500
Kevin
502500-600
Kevin
502600-700
Kevin
502700-800
Kevin
502800-900
Kevin
502900-000
Kevin
503000-100
Kevin
503100-200
Kevin
503200-300
Kevin
503300-400
Kevin
503400-500
Kevin
503500-600
Kevin
503600-700
Kevin
503700-800
Kevin
503800-900
Kevin
503900-000
Kevin
504000-100
Kevin
504100-200
Kevin
504200-300
Kevin
504300-400
Kevin
504400-500
Kevin
504500-600
Kevin
504600-700
Kevin
504700-800
Kevin
504800-900
Kevin
504900-000
Kevin
505000-100
Kevin
505100-200
Kevin
505200-300
Kevin
505300-400
Kevin
505400-500
Kevin
505500-600
Kevin
505600-700
Kevin
505700-800
Kevin
505800-900
Kevin
505900-000
Kevin
506000-100
Kevin
506100-200
Kevin
506200-300
Kevin
506300-400
Kevin
506400-500
Kevin
506500-600
Kevin
506600-700
Kevin
506700-800
Kevin
506800-900
Kevin
506900-000
Kevin
507000-100
Steven
507100-200
Steven
507200-300
Bob
507300-400
Bob
507400-500
Daniel
507500-600
Daniel
507600-700
Luiz
507700-800
Luiz
507800-900
Luiz
507900-000
Luiz
508000-100
Lutz
508100-200
Lutz
508200-300
Lutz
508300-400
Lutz
508400-500
Lutz
508500-600
Lutz
508600-700
Lutz
508700-800
Lutz
508800-900
Lutz
508900-000
Lutz
509000-100
Lutz
509100-200
Lutz
509200-300
Lutz
509300-400
Lutz
509400-500
Lutz
509500-600
Lutz
509600-700
Lutz
509700-800
Lutz
509800-900
Lutz
509900-000
Lutz
510000-100
Teodor
510100-200
Teodor
510200-300
Chris:
510300-400
Eric
510400-500
Luiz
510500-600
Luiz
510600-700
Luiz
510700-800
Luiz
510800-900
Teodor
510900-000
Teodor
511000-100
Steven
511100-200
Steven
511200-300
Steven
511300-400
Steven
511400-500
Steven
511500-600
Steven
511600-700
Steven
511700-800
Steven
511800-900
Eric
511900-000
Eric
512000-100
Bob
512100-200
Bob
512200-300
Daniel
512300-400
Daniel
512400-500
Teodor
512500-600
Teodor
512600-700
Luiz
512700-800
Luiz
512800-900
Luiz
512900-000
Luiz
513000-100
Kevin
513100-200
Kevin
513200-300
Kevin
513300-400
Kevin
513400-500
Kevin
513500-600
Kevin
513600-700
Kevin
513700-800
Kevin
513800-900
Kevin
513900-000
Kevin
514000-100
Kevin
514100-200
Kevin
514200-300
Kevin
514300-400
Kevin
514400-500
Kevin
514500-600
Kevin
514600-700
Kevin
514700-800
Kevin
514800-900
Kevin
514900-000
Kevin
515000-100
Kevin
515100-200
Kevin
515200-300
Kevin
515300-400
Kevin
515400-500
Kevin
515500-600
Kevin
515600-700
Kevin
515700-800
Kevin
515800-900
Kevin
515900-000
Kevin
516000-100
Kevin
516100-200
Kevin
516200-300
Kevin
516300-400
Kevin
516400-500
Kevin
516500-600
Kevin
516600-700
Kevin
516700-800
Kevin
516800-900
Kevin
516900-000
Kevin
517000-100
Kevin
517100-200
Kevin
517200-300
Kevin
517300-400
Kevin
517400-500
Kevin
517500-600
Kevin
517600-700
Kevin
517700-800
Kevin
517800-900
Kevin
517900-000
Kevin
518000-100
Kevin
518100-200
Kevin
518200-300
Kevin
518300-400
Kevin
518400-500
Kevin
518500-600
Kevin
518600-700
Kevin
518700-800
Kevin
518800-900
Kevin
518900-000
Kevin
519000-100
Steven
519100-200
Steven
519200-300
Steven
519300-400
Steven
519400-500
Steven
519500-600
Steven
519600-700
Steven
519700-800
Steven
519800-900
Eric
519900-000
Eric
520000-100
Wenjie
520100-200
Wenjie
520200-300
Wenjie
520300-400
Wenjie
520400-500
Wenjie
520500-600
Wenjie
520600-700
Wenjie
520700-800
Wenjie
520800-900
Wenjie
520900-000
Wenjie
521000-100
Wenjie
521100-200
Wenjie
521200-300
Wenjie
521300-400
Wenjie
521400-500
Wenjie
521500-600
Wenjie
521600-700
Wenjie
521700-800
Wenjie
521800-900
Wenjie
521900-000
Wenjie
522000-100
Wenjie
522100-200
Wenjie
522200-300
Wenjie
522300-400
Wenjie
522400-500
Wenjie
522500-600
Wenjie
522600-700
Wenjie
522700-800
Wenjie
522800-900
Wenjie
522900-000
Wenjie
523000-100
Wenjie
523100-200
Wenjie
523200-300
Wenjie
523300-400
Wenjie
523400-500
Wenjie
523500-600
Wenjie
523600-700
Wenjie
523700-800
Wenjie
523800-900
Wenjie
523900-000
Wenjie
524000-100
Wenjie
524100-200
Wenjie
524200-300
Wenjie
524300-400
Wenjie
524400-500
Wenjie
524500-600
Wenjie
524600-700
Wenjie
524700-800
Wenjie
524800-900
Wenjie
524900-000
Wenjie
525000-100
Wenjie
525100-200
Wenjie
525200-300
Wenjie
525300-400
Wenjie
525400-500
Wenjie
525500-600
Wenjie
525600-700
Wenjie
525700-800
Wenjie
525800-900
Wenjie
525900-000
Wenjie
526000-100
Wenjie
526100-200
Wenjie
526200-300
Wenjie
526300-400
Wenjie
526400-500
Wenjie
526500-600
Wenjie
526600-700
Wenjie
526700-800
Wenjie
526800-900
Wenjie
526900-000
Wenjie
527000-100
Wenjie
527100-200
Wenjie
527200-300
Wenjie
527300-400
Wenjie
527400-500
Wenjie
527500-600
Wenjie
527600-700
Wenjie
527700-800
Wenjie
527800-900
Wenjie
527900-000
Wenjie
528000-100
Wenjie
528100-200
Wenjie
528200-300
Wenjie
528300-400
Wenjie
528400-500
Wenjie
528500-600
Wenjie
528600-700
Wenjie
528700-800
Wenjie
528800-900
Wenjie
528900-000
Wenjie
529000-100
Wenjie
529100-200
Wenjie
529200-300
Wenjie
529300-400
Wenjie
529400-500
Wenjie
529500-600
Wenjie
529600-700
Wenjie
529700-800
Wenjie
529800-900
Wenjie
529900-000
Wenjie
530000-100
Wenjie
530100-200
Wenjie
530200-300
Wenjie
530300-400
Wenjie
530400-500
Wenjie
530500-600
Wenjie
530600-700
Wenjie
530700-800
Wenjie
530800-900
Wenjie
530900-000
Wenjie
531000-100
Wenjie
531100-200
Wenjie
531200-300
Wenjie
531300-400
Wenjie
531400-500
Wenjie
531500-600
Wenjie
531600-700
Wenjie
531700-800
Wenjie
531800-900
Wenjie
531900-000
Wenjie
532000-100
Wenjie
532100-200
Wenjie
532200-300
Wenjie
532300-400
Wenjie
532400-500
Wenjie
532500-600
Wenjie
532600-700
Wenjie
532700-800
Wenjie
532800-900
Wenjie
532900-000
Wenjie
533000-100
Wenjie
533100-200
Wenjie
533200-300
Wenjie
533300-400
Wenjie
533400-500
Wenjie
533500-600
Wenjie
533600-700
Wenjie
533700-800
Wenjie
533800-900
Wenjie
533900-000
Wenjie
534000-100
Wenjie
534100-200
Wenjie
534200-300
Wenjie
534300-400
Wenjie
534400-500
Wenjie
534500-600
Wenjie
534600-700
Wenjie
534700-800
Wenjie
534800-900
Wenjie
534900-000
Wenjie
535000-100
Wenjie
535100-200
Wenjie
535200-300
Wenjie
535300-400
Wenjie
535400-500
Wenjie
535500-600
Wenjie
535600-700
Wenjie
535700-800
Wenjie
535800-900
Wenjie
535900-000
Wenjie
536000-100
Wenjie
536100-200
Wenjie
536200-300
Wenjie
536300-400
Wenjie
536400-500
Wenjie
536500-600
Wenjie
536600-700
Wenjie
536700-800
Wenjie
536800-900
Wenjie
536900-000
Wenjie
537000-100
Wenjie
537100-200
Wenjie
537200-300
Wenjie
537300-400
Wenjie
537400-500
Wenjie
537500-600
Wenjie
537600-700
Wenjie
537700-800
Wenjie
537800-900
Wenjie
537900-000
Wenjie
538000-100
Wenjie
538100-200
Wenjie
538200-300
Wenjie
538300-400
Wenjie
538400-500
Wenjie
538500-600
Wenjie
538600-700
Wenjie
538700-800
Wenjie
538800-900
Wenjie
538900-000
Wenjie
539000-100
Wenjie
539100-200
Wenjie
539200-300
Wenjie
539300-400
Wenjie
539400-500
Wenjie
539500-600
Wenjie
539600-700
Wenjie
539700-800
Wenjie
539800-900
Wenjie
539900-000
Wenjie
540000-100
Bob
540100-200
Bob
540200-300
Eric
540300-400
Eric
540400-500
Eric
540500-600
Eric
540600-700
Eric
540700-800
Eric
540800-900
Eric
540900-000
Eric
541000-100
Daniel
541100-200
Daniel
541200-300
Teodor
541300-400
Teodor
541400-500
Luiz
541500-600
Luiz
541600-700
Luiz
541700-800
Luiz
541800-900
Dylan
541900-000
Eric
542000-100
Lutz
542100-200
Lutz
542200-300
Lutz
542300-400
Lutz
542400-500
Lutz
542500-600
Lutz
542600-700
Lutz
542700-800
Lutz
542800-900
Lutz
542900-000
Lutz
543000-100
Lutz
543100-200
Lutz
543200-300
Lutz
543300-400
Lutz
543400-500
Lutz
543500-600
Lutz
543600-700
Lutz
543700-800
Lutz
543800-900
Lutz
543900-000
Lutz
544000-100
Kevin
544100-200
Kevin
544200-300
Kevin
544300-400
Kevin
544400-500
Kevin
544500-600
Kevin
544600-700
Kevin
544700-800
Kevin
544800-900
Kevin
544900-000
Kevin
545000-100
Kevin
545100-200
Kevin
545200-300
Kevin
545300-400
Kevin
545400-500
Kevin
545500-600
Kevin
545600-700
Kevin
545700-800
Kevin
545800-900
Kevin
545900-000
Kevin
546000-100
Kevin
546100-200
Kevin
546200-300
Kevin
546300-400
Kevin
546400-500
Kevin
546500-600
Kevin
546600-700
Kevin
546700-800
Kevin
546800-900
Kevin
546900-000
Kevin
547000-100
Kevin
547100-200
Kevin
547200-300
Kevin
547300-400
Kevin
547400-500
Kevin
547500-600
Kevin
547600-700
Kevin
547700-800
Kevin
547800-900
Kevin
547900-000
Kevin
548000-100
Kevin
548100-200
Kevin
548200-300
Kevin
548300-400
Kevin
548400-500
Kevin
548500-600
Kevin
548600-700
Kevin
548700-800
Kevin
548800-900
Kevin
548900-000
Kevin
549000-100
Kevin
549100-200
Kevin
549200-300
Kevin
549300-400
Kevin
549400-500
Kevin
549500-600
Kevin
549600-700
Kevin
549700-800
Kevin
549800-900
Kevin
549900-000
Kevin
550000-100
Wenjie
550100-200
Wenjie
550200-300
Wenjie
550300-400
Wenjie
550400-500
Wenjie
550500-600
Wenjie
550600-700
Wenjie
550700-800
Wenjie
550800-900
Wenjie
550900-000
Wenjie
551000-100
Wenjie
551100-200
Wenjie
551200-300
Wenjie
551300-400
Wenjie
551400-500
Wenjie
551500-600
Wenjie
551600-700
Wenjie
551700-800
Wenjie
551800-900
Wenjie
551900-000
Wenjie
552000-100
Wenjie
552100-200
Wenjie
552200-300
Wenjie
552300-400
Wenjie
552400-500
Wenjie
552500-600
Wenjie
552600-700
Wenjie
552700-800
Wenjie
552800-900
Wenjie
552900-000
Wenjie
553000-100
Wenjie
553100-200
Wenjie
553200-300
Wenjie
553300-400
Wenjie
553400-500
Wenjie
553500-600
Wenjie
553600-700
Wenjie
553700-800
Wenjie
553800-900
Wenjie
553900-000
Wenjie
554000-100
Wenjie
554100-200
Wenjie
554200-300
Wenjie
554300-400
Wenjie
554400-500
Wenjie
554500-600
Wenjie
554600-700
Wenjie
554700-800
Wenjie
554800-900
Wenjie
554900-000
Wenjie
555000-100
Wenjie
555100-200
Wenjie
555200-300
Wenjie
555300-400
Wenjie
555400-500
Wenjie
555500-600
Wenjie
555600-700
Wenjie
555700-800
Wenjie
555800-900
Wenjie
555900-000
Wenjie
556000-100
Wenjie
556100-200
Wenjie
556200-300
Wenjie
556300-400
Wenjie
556400-500
Wenjie
556500-600
Wenjie
556600-700
Wenjie
556700-800
Wenjie
556800-900
Wenjie
556900-000
Wenjie
557000-100
Wenjie
557100-200
Wenjie
557200-300
Wenjie
557300-400
Wenjie
557400-500
Wenjie
557500-600
Wenjie
557600-700
Wenjie
557700-800
Wenjie
557800-900
Wenjie
557900-000
Wenjie
558000-100
Wenjie
558100-200
Wenjie
558200-300
Wenjie
558300-400
Wenjie
558400-500
Wenjie
558500-600
Wenjie
558600-700
Wenjie
558700-800
Wenjie
558800-900
Wenjie
558900-000
Wenjie
559000-100
Wenjie
559100-200
Wenjie
559200-300
Wenjie
559300-400
Wenjie
559400-500
Wenjie
559500-600
Wenjie
559600-700
Wenjie
559700-800
Wenjie
559800-900
Wenjie
559900-000
Wenjie
560000-100
Steven
560100-200
Steven
560200-300
Steven
560300-400
Steven
560400-500
Steven
560500-600
Steven
560600-700
Steven
560700-800
Steven
560800-900
Eric
560900-000
Eric
561000-100
Daniel
561100-200
Daniel
561200-300
Dylan
561300-400
Dylan
561400-500
Teodor
561500-600
Teodor
561600-700
Luiz
561700-800
Luiz
561800-900
Luiz
561900-000
Luiz
562000-100
Bob
562100-200
Bob
562200-300
Steven
562300-400
Steven
562400-500
Steven
562500-600
Steven
562600-700
Steven
562700-800
Steven
562800-900
Steven
562900-000
Steven
Contributions by
EricEric Roosendaal, Netherlands (author) LutzLutz Nebe, Germany
KevinKevin Hebb, Alberta, Canada BobBob Coffman, USA
WenjieFang Wenjie, China StevenSteven Cuthbert, England
LuizLuiz Antonio Souza, Brazil Chris:Christopher Peace, UK
TeodorTeodor Baev DanielDaniel Podobinski
DylanDylan Delgado   

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