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%I #29 Jun 07 2019 11:00:23
%S 2,4,6,16,12,18,24,40,54,36,102,110,60,72,108,140,120,156,144,200,216,
%T 210,240,180,456,288,336,300,396,480,882,360,468,700
%N a(n) = smallest number k such that number of prime factors of 2^k-1 is exactly n (counted with multiplicity).
%p N:= 24: # to get a(1) to a(N)
%p unknown:= N:
%p for k from 2 while unknown > 0 do
%p q:= numtheory:-bigomega(2^k-1);
%p if q <= N and not assigned(A[q]) then
%p A[q]:= k;
%p unknown:= unknown - 1;
%p fi
%p od:
%p seq(A[i],i=1..N); # _Robert Israel_, Oct 24 2014
%o (PARI) a(n) = {k = 1; while(bigomega(2^k-1) != n, k++); k;} \\ _Michel Marcus_, Nov 04 2013
%Y Cf. A000225, A003260, A016047, A046051, A049479, A088863, A136030, A136031.
%K nonn,more,hard
%O 1,1
%A _Artur Jasinski_, Dec 11 2007
%E a(15)-a(20) from _Michel Marcus_, Nov 04 2013
%E a(21)-a(24) from _Derek Orr_, Oct 23 2014
%E a(25)-a(34) from _Jinyuan Wang_, Jun 07 2019
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