2,1

T. D. Noe, Table of n, a(n) for n=2..500 (derived from Brillhart et al.)

Eric Weisstein's World of Mathematics, Mersenne Number

a(6)=3 since 2^6 - 1 = 63 = 3^2*7

a = {}; Do[w = 2^n - 1; c = FactorInteger[w]; b = c[[1]][[1]]; AppendTo[a, b], {n, 2, 65}]; a - Artur Jasinski (grafix(AT)csl.pl), Dec 11 2007

Cf. A005420.

Sequence in context: A088837 A019158 A086153 this_sequence A125314 A050393 A110778

Adjacent sequences: A049476 A049477 A049478 this_sequence A049480 A049481 A049482

nonn

Olivier Gerard (olivier.gerard(AT)gmail.com)

More terms from Michael Lugo (mlugo(AT)thelabelguy.com), Dec 22 1999