P1365

[themaster]

has P1365 ever been factored
P1365 is a factor of M13# (M30030)
only a c145 factor remains
could someone please tell me haw much ecm should be done and then how long factoring with ggnfs should take

[ValerieVonck]

See: (IMHO)

http://www.mersenne.org/ecm.htm
ftp://mersenne.org/gimps/lowm.txt
ftp://mersenne.org/gimps/lowp.txt
http://www.leyland.vispa.com/numth/f...s/mersenne.txt

Regards
C.

[themaster]

Originally Posted by CedricVonck

See: (IMHO)

http://www.mersenne.org/ecm.htm
ftp://mersenne.org/gimps/lowm.txt
ftp://mersenne.org/gimps/lowp.txt
http://www.leyland.vispa.com/numth/f...s/mersenne.txt

Regards
C.

none of the above sites have factorizations for P1365 since the exponent is above 1200
it is also not in lowp.txt
i have searched quite a bit in that sort of place to find this factorization
if i have missed something please just point it out

[themaster]

is there a file that has more factors in it than lowp.txt

[wblipp]

I'd also check Will Edgington's Mersenne Page. His December 15th update still lists the C145. Will lists this in lowM.txt under M( 2730 ).

William

[fivemack]

Originally Posted by themaster

has P1365 ever been factored
P1365 is a factor of M13# (M30030)
only a c145 factor remains
could someone please tell me haw much ecm should be done and then how long factoring with ggnfs should take

I don't think it has been factored - at least, I googled the prime factor 4663895387971 of the primitive part, and didn't find any other factors mentioned in the two hits.

I'd run 2500 curves at 43e6, then polynomial search and sieve; for numbers this big there's still a bit of manual intervention involved, but you ought on one core2-class computer to have an answer by the end of February.

[xilman]

Originally Posted by themaster

has P1365 ever been factored
P1365 is a factor of M13# (M30030)
only a c145 factor remains
could someone please tell me haw much ecm should be done and then how long factoring with ggnfs should take

Please post the decimal representation of your c145.

If it's been factored anywhere by anyone, there's a good change I can dig out the factors very rapidly. Otherwise, finishing with GNFS should take about a week though, note, this is not an offer to do so.

Paul

[fivemack]

1747155976140576469705652320728306638552264970224296329802371579918986789611343920344321306746421947396330663454762878038087163972889931354625731

(at least, if it's the C145 obtained by dividing the easy composite factor 181593921839918736236929091161 out of

? allocatemem(2^30)
? subst(factor(x^1365+1)[16,1],x,2)
%1 = 317272905773418767822978345073813150808603524182013657201301484306799996421428192478516111083394382351461246163863988920383239505652476088366455893282056213135168039135263691

[xilman]

Originally Posted by fivemack

1747155976140576469705652320728306638552264970224296329802371579918986789611343920344321306746421947396330663454762878038087163972889931354625731

(at least, if it's the C145 obtained by dividing the easy composite factor 181593921839918736236929091161 out of

? allocatemem(2^30)
? subst(factor(x^1365+1)[16,1],x,2)
%1 = 317272905773418767822978345073813150808603524182013657201301484306799996421428192478516111083394382351461246163863988920383239505652476088366455893282056213135168039135263691

Thanks.

Paul

[philmoore]

I ran a fair amount of ECM on this number a few years ago, and doubt that there are any factors < 35 digits, but I don't remember exactly how far I got. My guess is that you probably should run up to the 45 or 50 digit level before starting GNFS. I would be interested in what you find.

[themaster]

thanks guys for ur help
during today i have almost finished 35 digit ecm on my 2 pcs

i am sure i looked at lowm.txt for m2730

yes that is the number
any help would be appreciated

i underestimated the length of time needed for gnfs because i cant have my pcs running all the time and i dont have a core2duo i think it might take me the whole of 2008
if i fail with ecm i will be forced to stop
even the ecm will take a lot of time