A135386 Mersenne composites A065341 with 4 or more prime factors.

10384593717069655257060992658440191, 2854495385411919762116571938898990272765493247, 182687704666362864775460604089535377456991567871

Offset

1,1

Links

Amiram Eldar, Table of n, a(n) for n = 1..102

Maple

A135386 := proc(n) local i;
i := 2^(ithprime(n))-1:
if (nops(numtheory[factorset](i)) > 3) then
   RETURN (i)
fi: end: seq(A135386(n), n=1..37); # Jani Melik, Feb 09 2011

Mathematica

k = {}; Do[If[ ! PrimeQ[2^Prime[n] - 1], c = FactorInteger[2^Prime[n] - 1]; d = Length[c]; If[d >3, AppendTo[k, 2^Prime[n] - 1]]], {n, 1, 40}]; k

Crossrefs

Subsequence of A065341.

Cf. A000225, A054723, A134852, A135975, A135976, A135977, A135979.

Sequence in context: A083103 A115532 A074194 * A378477 A095462 A115543

Adjacent sequences: A135383 A135384 A135385 * A135387 A135388 A135389

Keyword

nonn

Author

Artur Jasinski, Dec 09 2007

Status

approved