A135386 - OEIS

%I #16 Oct 10 2024 08:18:03

%S 10384593717069655257060992658440191,

%T 2854495385411919762116571938898990272765493247,

%U 182687704666362864775460604089535377456991567871

%N Mersenne composites A065341 with 4 or more prime factors.

%H Amiram Eldar, <a href="/A135386/b135386.txt">Table of n, a(n) for n = 1..102</a>

%p A135386 := proc(n) local i;

%p i := 2^(ithprime(n))-1:

%p if (nops(numtheory[factorset](i)) > 3) then

%p    RETURN (i)

%p fi: end: seq(A135386(n), n=1..37); # _Jani Melik_, Feb 09 2011

%t 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

%Y Subsequence of A065341.

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

%K nonn,changed

%O 1,1

%A _Artur Jasinski_, Dec 09 2007