3x+1 Class records calculation progress map
Status of the 3x+1 class record progress as of: Apr 18, 2024.
Intervals are indicated in units of 1,000,000,000,000 (1 E+12 or 1 trillion numbers).
Calculation of a single block of 10,000 units takes approximately 5-10 days on an NVIDIA graphics 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
March 27 2024 : All blocks up to 25,300 completed. Three more class records confirmed.
February 7 2024 : All blocks up to 24,140 completed.
December 10 2023 : All blocks up to 24,060 completed. Two more class records confirmed.
October 23 2023 : All blocks up to 22,840 completed. Two more class records confirmed.
October 1 2023 : All blocks up to 22,200 completed. Four more class records confirmed.
July 24 2023 : All blocks up to 21,120 completed.
May 18 2023 : All blocks up to 21,000 completed. Three more class records confirmed.
April 30 2023 : All blocks up to 19,940 completed. One more class record confirmed.
March 22 2023 : All blocks up to 19,860 completed. Five class records confirmed.
January 23 2023 : All blocks up to 18,500 completed. Every number up to 64 bits checked. Five class records confirmed.
Show/Hide earlier milestones
August 2022 : All blocks up to 16,400 completed. Five class records confirmed.
May 2022 : All blocks up to 15,000 completed. Seven class records confirmed.
May 2022 : New Delay record (Delay 2442) found by Kevin.
March 2022 : All blocks up to 13,480 completed. Five class records confirmed.
February 2022 : New Delay record (Delay 2429) found by Kevin.
January 2022 : All blocks up to 12,300 completed. Six more class records confirmed.
December 2021 : All blocks up to 10,820 completed. Eight class records confirmed.
September 2021 : New Delay record (Delay 2426) found by Kevin.
August 2021 : All blocks up to 9000,000 completed. Six class records confirmed.
July 2021 : All blocks up to 8000,000 completed. Eight class records confirmed.
May 2021 : All blocks up to 6640,000 completed. Twelve class records confirmed.
April 2021 : New Delay record (Delay 2389) found by Kevin.
February 2021 : New Delay record (Delay 2363) found by Kevin.
February 2021 : New Delay record (Delay 2337) found by Volkmar.
January 2021 : All blocks up to 4700,000 completed. Eight class records confirmed.
December 2020 : All blocks up to 3940,000 completed. Eleven class records confirmed.
December 2020 : New Delay record (Delay 2334) found by Kevin.
November 2020 : All blocks up to 2900,000 completed. Delay record 2331 and twelve more class records confirmed
September 2020 : All blocks up to 2300,000 completed. Eleven class records confirmed
September 2020 : All blocks up to 2000,000 completed. Fifteen class records confirmed
August 2020 : All blocks up to 1620,000 completed. Sixteen class records confirmed
July 2020 : All blocks up to 1300,000 completed. 37 class records confirmed
June 30 2020 : New Delay record (Delay 2330) found by Eric.
June 28 2020 : New Delay record (Delay 2286) found by Kevin.
May 30 2020 : New Delay record (Delay 2283) found by Kevin.
May 2020 : All blocks up to 820,000 completed. Sixteen class record confirmed. All class records below 2100 known.
March 2020 : All blocks up to 698,000 completed. Twelve more class records confirmed.
December 2019 : All blocks up to 602,000 completed. Nine class records confirmed.
September 2019 : All blocks up to 561,200 completed. Delay record 2277 and ten more class record confirmed.
May 2019 : All blocks up to 500,000 completed. Delay record 2264 and eight more class records confirmed.
March 2019 : All blocks up to 455,200 completed. Lowest missing class record (2070) and four others confirmed.
December 2018 : All blocks up to 387,000 completed. Delay record 2261 and nine more class records confirmed.
October 2018 : All blocks up to 366,400 completed. Six more class records confirmed.
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. Three class records confirmed.
March 2016 : All blocks up to 275,200 completed. Four more class records confirmed.
March 19 2016 : 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)
Range 500000-600000
completed (view)
Range 600000-700000
completed (view)
Range 700000-800000
completed (view)
Range 800000-900000
completed (view)
Range 900000-1000000
completed (view)
Range 1000000-2000000
completed (view)
Range 2000000-3000000
completed (view)
Range 3000000-4000000
completed (view)
Range 4000000-5000000
completed (view)
Range 5000000-10000000
completed (view)
Range 10000000-15000000
completed (view)
Range 15000000-20000000
completed (view)
Range 20000000-25000000
completed (view)
 
Not yet assigned Assigned,
not yet started
Assigned,
in progress
Entire interval
completed
Interval completed
class record found
25000000-10000
Daniel
25010000-20000
Daniel
25020000-30000
Luiz
25030000-40000
Luiz
25040000-50000
Carsten
25050000-60000
Carsten
25060000-70000
Carsten
25070000-80000
Carsten
25080000-90000
Wenjie
25090000-00000
Wenjie
25100000-10000
Daniel
25110000-20000
Daniel
25120000-30000
Lutz
25130000-40000
Lutz
25140000-50000
Eric
25150000-60000
Eric
25160000-70000
Daniel
25170000-80000
Daniel
25180000-90000
Wenjie
25190000-00000
Wenjie
25200000-10000
Luiz
25210000-20000
Luiz
25220000-30000
Eric
25230000-40000
Eric
25240000-50000
Eric
25250000-60000
Carsten
25260000-70000
Wenjie
25270000-80000
Wenjie
25280000-90000
Eric
25290000-00000
Eric
25300000-10000
Carsten
25310000-20000
Carsten
25320000-30000
Carsten
25330000-40000
Carsten
25340000-50000
Carsten
25350000-60000
Carsten
25360000-70000
Carsten
25370000-80000
Carsten
25380000-90000
Carsten
25390000-00000
Carsten
25400000-10000
Luiz
25410000-20000
Luiz
25420000-30000
Daniel
25430000-40000
Daniel
25440000-50000
Lutz
25450000-60000
Lutz
25460000-70000
Vincent
25470000-80000
Vincent
25480000-90000
Wenjie
25490000-00000
Wenjie
25500000-10000
Kevin
25510000-20000
Kevin
25520000-30000
Kevin
25530000-40000
Kevin
25540000-50000
Kevin
25550000-60000
Kevin
25560000-70000
Kevin
25570000-80000
Kevin
25580000-90000
Kevin
25590000-00000
Kevin
25600000-10000
Kevin
25610000-20000
Kevin
25620000-30000
Kevin
25630000-40000
Kevin
25640000-50000
Kevin
25650000-60000
Kevin
25660000-70000
Kevin
25670000-80000
Kevin
25680000-90000
Kevin
25690000-00000
Kevin
25700000-10000
Kevin
25710000-20000
Kevin
25720000-30000
Kevin
25730000-40000
Kevin
25740000-50000
Kevin
25750000-60000
Kevin
25760000-70000
Kevin
25770000-80000
Kevin
25780000-90000
Kevin
25790000-00000
Kevin
25800000-10000
Kevin
25810000-20000
Kevin
25820000-30000
Kevin
25830000-40000
Kevin
25840000-50000
Kevin
25850000-60000
Kevin
25860000-70000
Kevin
25870000-80000
Kevin
25880000-90000
Kevin
25890000-00000
Kevin
25900000-10000
Kevin
25910000-20000
Kevin
25920000-30000
Kevin
25930000-40000
Kevin
25940000-50000
Kevin
25950000-60000
Kevin
25960000-70000
Kevin
25970000-80000
Kevin
25980000-90000
Kevin
25990000-00000
Kevin
26000000-10000
Kevin
26010000-20000
Kevin
26020000-30000
Kevin
26030000-40000
Kevin
26040000-50000
Kevin
26050000-60000
Kevin
26060000-70000
Kevin
26070000-80000
Kevin
26080000-90000
Kevin
26090000-00000
Kevin
26100000-10000
Kevin
26110000-20000
Kevin
26120000-30000
Kevin
26130000-40000
Kevin
26140000-50000
Kevin
26150000-60000
Kevin
26160000-70000
Kevin
26170000-80000
Kevin
26180000-90000
Kevin
26190000-00000
Kevin
26200000-10000
Kevin
26210000-20000
Kevin
26220000-30000
Kevin
26230000-40000
Kevin
26240000-50000
Kevin
26250000-60000
Kevin
26260000-70000
Kevin
26270000-80000
Kevin
26280000-90000
Kevin
26290000-00000
Kevin
26300000-10000
Kevin
26310000-20000
Kevin
26320000-30000
Kevin
26330000-40000
Kevin
26340000-50000
Kevin
26350000-60000
Kevin
26360000-70000
Kevin
26370000-80000
Kevin
26380000-90000
Kevin
26390000-00000
Kevin
26400000-10000
Kevin
26410000-20000
Kevin
26420000-30000
Kevin
26430000-40000
Kevin
26440000-50000
Kevin
26450000-60000
Kevin
26460000-70000
Kevin
26470000-80000
Kevin
26480000-90000
Kevin
26490000-00000
Kevin
26500000-10000
Kevin
26510000-20000
Kevin
26520000-30000
Kevin
26530000-40000
Kevin
26540000-50000
Kevin
26550000-60000
Kevin
26560000-70000
Kevin
26570000-80000
Kevin
26580000-90000
Kevin
26590000-00000
Kevin
26600000-10000
Kevin
26610000-20000
Kevin
26620000-30000
Kevin
26630000-40000
Kevin
26640000-50000
Kevin
26650000-60000
Kevin
26660000-70000
Kevin
26670000-80000
Kevin
26680000-90000
Kevin
26690000-00000
Kevin
26700000-10000
Kevin
26710000-20000
Kevin
26720000-30000
Kevin
26730000-40000
Kevin
26740000-50000
Kevin
26750000-60000
Kevin
26760000-70000
Kevin
26770000-80000
Kevin
26780000-90000
Kevin
26790000-00000
Kevin
26800000-10000
Kevin
26810000-20000
Kevin
26820000-30000
Kevin
26830000-40000
Kevin
26840000-50000
Kevin
26850000-60000
Kevin
26860000-70000
Kevin
26870000-80000
Kevin
26880000-90000
Kevin
26890000-00000
Kevin
26900000-10000
Kevin
26910000-20000
Kevin
26920000-30000
Kevin
26930000-40000
Kevin
26940000-50000
Kevin
26950000-60000
Kevin
26960000-70000
Kevin
26970000-80000
Kevin
26980000-90000
Kevin
26990000-00000
Kevin
27000000-10000
Wenjie
27010000-20000
Wenjie
27020000-30000
Daniel
27030000-40000
Daniel
27040000-50000
Wenjie
27050000-60000
Wenjie
27060000-70000
Luiz
27070000-80000
Luiz
27080000-90000
27090000-00000
27100000-10000
Carsten
27110000-20000
Carsten
27120000-30000
Carsten
27130000-40000
Carsten
27140000-50000
Carsten
27150000-60000
Carsten
27160000-70000
Carsten
27170000-80000
Carsten
27180000-90000
Carsten
27190000-00000
Carsten
Contributions by
EricEric Roosendaal, Netherlands (author) LutzLutz Nebe, Germany
KevinKevin Hebb, Alberta, Canada WenjieFang Wenjie, China
LuizLuiz Antonio Souza, Brazil DanielDaniel Podobinski
VincentVincent Phillips CarstenCarsten Derlich

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