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Old 2020-10-11, 10:40   #500
unconnected's Avatar
May 2009
Russia, Moscow

2×5×11×23 Posts

Really lucky hit for aliquot sequence 79^91:i5

GMP-ECM 7.0.4 [configured with GMP 6.1.2, --enable-asm-redc] [ECM]
Input number is 265068640573758407535905984867282858553267450389668652958394878324092361572221738127508595352727313041526471350792042955118039583885472232715529 (144 digits)
Run 12 out of 150:
Using B1=43000000, B2=240490660426, polynomial Dickson(12), sigma=1:734709831
Step 1 took 143604ms
Step 2 took 52384ms
********** Factor found in step 2: 10622969779722833224233821696670456635150835905540542178233981211
Found prime factor of 65 digits: 10622969779722833224233821696670456635150835905540542178233981211
Prime cofactor 24952404654273090201857266161762430747111830388231810834477663075621591193735339 has 80 digits
It is my biggest ECM-factor so far. Previously I've several P63, P62, and P61 factors (none of them were found with B1>11e7 limit). Sadly even this record factor is not big enough to enter top10 yearly list.
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