Lucky ECM hit

Dubslow · 2014-10-09, 04:41

Running aliquot sequence 78816 and found this lucky ECM hit:

Code:

10/08/14 23:30:12 v1.34.5 @ Gravemind, current ECM pretesting depth: 30.46
10/08/14 23:30:12 v1.34.5 @ Gravemind, scheduled 904 curves at B1=1000000 toward target pretesting depth of 35.69
10/08/14 23:31:12 v1.34.5 @ Gravemind, prp39 = 397014779879110918974351728195016076189 (curve 8 stg2 B1=1000000 sigma=
2353567942 thread=1)
10/08/14 23:31:12 v1.34.5 @ Gravemind, Finished 56 curves using Lenstra ECM method on C116 input, B1=1M, B2=gmp-ecm de
fault
10/08/14 23:31:12 v1.34.5 @ Gravemind, final ECM pretested depth: 30.77

The penultimate factor of the group order is just over 1% from the B1 bound.

It's also lucky that I happened to be watching it at the time, or I wouldn't have noticed.

legendarymudkip · 2014-10-19, 18:41

Code:

current ECM pretesting depth: 20.24
scheduled 214 curves at B1=50000 toward target pretesting depth of 25.85
prp31 = 2193059645364365637108057957697 (curve 56 stg2 B1=50000 sigma=3634287944 thread=0)
Finished 56 curves using Lenstra ECM method on C84 input, B1=50K, B2=gmp-ecm default
final ECM pretested depth: 21.55

A similar case on an aliquot sequence I was running.

Batalov · 2014-10-19, 18:58

If you think 30-ish-digit hits are lucky, I don't know what you will call that one.

legendarymudkip · 2014-10-19, 19:10

Lucky doesn't signify lottery chances

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2014-10-19, 18:58	#3
Batalov "Serge" Mar 2008 Phi(4,2^7658614+1)/2 2×3×5²×67 Posts	If you think 30-ish-digit hits are lucky, I don't know what you will call that one.

2014-10-19, 19:10	#4
legendarymudkip Jun 2014 2³×3×5 Posts	Lucky doesn't signify lottery chances