is 2 255517 - 1
has 76919 decimal digits
takes 0.002 GHz-days to do one PRP test
Last-known PrimeNet details:
Exponent is not assigned to anyone
0 primality tests remaining
ResidueStatus
L-L34DB51A055470D68double-checked
PRP-unknown--unknown-

 Trial FactoringP-1 FactoringCombined
LimitGHz-daysProbabilityB1B2GHz-daysProbabilityGHz-daysProbability
Actual270935.165374.2857%1000000000201454308905850108,761.119627.9464%109,696.284981.4719%
Target2440.000059.0909%45001100000.000110.1945%0.000163.2614%
Difference+26+935.1653+15.1948%+999995500+201454308795850+108,761.1195+17.7520%+109,696.2848+18.2106%

Known prime factors:
No known factors for M255517

P-1 results:
 GHz-DaysworthFactor
probability
dateuseridcompidb1b2estagefactordigitsbits*spentsaved
2000-12-14ANONYMOUSv4_computers950003800000---0.003--1.513%
2001-06-17ANONYMOUSv4_computers10000010000000---0.006--1.894%
2002-06-02ANONYMOUSv4_computers327683276800---0.002--1.020%
2002-08-10ANONYMOUSv4_computers655366553600---0.004--1.526%
2003-03-07ANONYMOUSv4_computers13107213107200---0.008--2.152%
2003-11-08ANONYMOUSv4_computers26214426214400---0.017--2.892%
2011-02-09Jocelyn LaroucheManual testing20000002000000---0.020--1.898%
2012-02-26Jocelyn LaroucheManual testing24360122436012---0.024--2.049%
2013-09-05c10ck3rManual testing10000000200000000---0.202--6.539%
2021-12-05Seth_TrManual testing120000000120000000---1.189--6.340%
2021-12-05Seth_TrManual testing12000000057783635910---32.32--15.134%
2022-04-02-Anonymous-DL560G81000000000201454308905850---108,761--27.946%


P+1 Factoring results:
dateuseridcompidb1b2startfactorSmoothdigitsbits*ghz-days
2023-01-27masserManual testing3000000099000000027--0.788
2023-02-05masserManual testing3000000096000000018429--0.775
2023-02-07masserManual testing3000000099000000065--0.788


Trial Factoring results:
 BitsFactorGHz-Daysworth
dateuseridcompidfromtofactorbits*digitsspentsaved
1999-11-24ANONYMOUSv4_computers252253--0.002--
2000-04-27ANONYMOUSv4_computers21254--0.009--
2000-12-14ANONYMOUSv4_computers21255--0.019--
2001-02-18ANONYMOUSv4_computers21256--0.038--
2002-03-16ANONYMOUSv4_computers21257--0.075--
2016-02-23Mark RoseManual testing257258--0.075--
2009-01-01Sturle Sundegobi.ifi258259--0.150--
2009-01-25Sturle Sundeginjtje.ifi259260--0.301--
2013-09-18lycornasteroid260261--0.601--
2015-08-25NRManual testing261262--1.202--
2016-01-30Gordon SpenceManual testing262263--3.842--
2016-01-30Gordon SpenceManual testing263264--7.684--
2018-03-15Gordon SpenceManual testing264265--14.62--
2020-01-01Gordon SpenceManual testing265266--29.25--
2022-03-12Anton RepkoManual testing266270--877.4--


ECM factoring results:
Total ECM effort:1,055.343 GHz-days
Estimated T-Level:34.220
DigitsB1CompleteFacMiss
2011000203.9760.000%
255000044.2320.000%
302500006.8540.106%
3510000000.84442.995%
4030000000.08691.759%
45110000000.00799.264%


ECM Summary

B1B2factorcurvesGHz-days
5000050000002832.062
2500002500000058421.27
100000028420113157001,032


Lucas-Lehmer results:
dateuseridcompidres64spent (GHz-days)
1997-01-01Brian J. Beesleysamson34DB51A055470D680.002
2001-10-13ANONYMOUSv4_computers34DB51A055470D680.002


PRP results:
No PRP results for M255517


P-1 factor-bounds graph:
B1 = 1000000000, B2 = 201454308905850 (P-1 stage 2)
B1 = 120000000, B2 = 57783635910 (P-1 stage 2)
B1 = 1000000000 (P-1 stage 1)
B1 = 120000000 (P-1 stage 1)
B1 = 10000000, B2 = 200000000 (P-1 stage 2)
B1 = 10000000 (P-1 stage 1)
B1 = 2436012 (P-1 stage 1)
B1 = 2000000 (P-1 stage 1)
B1 = 262144, B2 = 26214400 (P-1 stage 2)
B1 = 131072, B2 = 13107200 (P-1 stage 2)
B1 = 100000, B2 = 10000000 (P-1 stage 2)
B1 = 65536, B2 = 6553600 (P-1 stage 2)
B1 = 95000, B2 = 3800000 (P-1 stage 2)
B1 = 262144 (P-1 stage 1)
B1 = 32768, B2 = 3276800 (P-1 stage 2)
B1 = 131072 (P-1 stage 1)
B1 = 100000 (P-1 stage 1)
B1 = 95000 (P-1 stage 1)
B1 = 65536 (P-1 stage 1)
B1 = 32768 (P-1 stage 1)
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TF factor-bounds graph:
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this exponent TF target: 44
TF double-checked to: 67.8
ECM T-Level=34.22 ~= 97-bit
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Last modified: 2023-04-26T21:34:10+00:00