login
A136030
Smallest prime factor of composite Mersenne numbers.
6
23, 47, 233, 223, 13367, 431, 2351, 6361, 179951, 193707721, 228479, 439, 2687, 167, 11447, 7432339208719, 2550183799, 745988807, 3391, 263, 32032215596496435569, 5625767248687, 86656268566282183151, 18121, 852133201, 150287, 2349023, 730753, 359, 43441, 383
OFFSET
1,1
LINKS
MATHEMATICA
a = {}; Do[If[PrimeQ[n] && !PrimeQ[2^n - 1], w = 2^n - 1; c = FactorInteger[w]; b = c[[1]][[1]]; AppendTo[a, b]], {n, 2, 130}]; a
PROG
(PARI) lista() = {vi = readvec("c:/gp/bfiles/b054723.txt"); vm = vector(#vi, i, 2^vi[i]-1); for (i=1, #vm, print1(factor(vm[i])[1, 1], ", "); ); } \\ Michel Marcus, May 14 2014
CROSSREFS
Sequence in context: A065017 A140618 A042052 * A054693 A180945 A052229
KEYWORD
nonn
AUTHOR
Artur Jasinski, Dec 11 2007
EXTENSIONS
More terms from Michel Marcus, May 14 2014
Terms to a(150) in b-file from Charles R Greathouse IV, May 14 2014
a(151)-a(188) in b-file added at the suggestion of Eric Chen by Max Alekseyev, Apr 25 2022
STATUS
approved