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%I #27 Jan 18 2019 13:59:05
%S 2,2,3,2,2,3,3,3,2,2,3,3,3,2,2,2,2,2,5,2,2,2,2,5,4,5,2,4,3,4,5,3,2,2,
%T 3,6,2,4,4,6,2,5,3,4,2,2,3,2,3,2,5,3,4,4,3,5,2,3,3,6,5,2,2,5,3,9,4,3,
%U 5,2,8,4,4,3,5,2,4,6,3,4,2,7,3,4,4,2,5,4,5,3,5,4,3,6,4,3,4,3,4,4
%N Number of prime factors (without multiplicity) in Mersenne composites A065341.
%C Currently the smallest prime exponent p for which 2^p-1 is incompletely factored is p = 1213. - _Gord Palameta_, Aug 06 2018
%H Gord Palameta, <a href="/A135975/b135975.txt">Table of n, a(n) for n = 1..183</a>
%H GIMPS, <a href="https://www.mersenne.org/M1213">Status of M1213</a>
%H S. S. Wagstaff, Jr., <a href="https://homes.cerias.purdue.edu/~ssw/cun/">Main Tables</a> from the Cunningham Project: cofactor of M1213 is C297
%F a(n) = A001221(A065341(n)). - _Michel Marcus_, Aug 07 2018
%t k = {}; Do[If[ ! PrimeQ[2^Prime[n] - 1], c = FactorInteger[2^Prime[n] - 1]; d = Length[c]; AppendTo[k, d]], {n, 1, 40}]; k
%t (PrimeNu /@ Select[2^Prime[Range[40]] - 1, ! PrimeQ[#] &]) (* _Jean-François Alcover_, Aug 13 2014
%o (PARI) forprime(p=1, 1e3, if(!ispseudoprime(2^p-1), print1(omega(2^p-1), ", "))) \\ _Felix Fröhlich_, Aug 12 2014
%Y Cf. A000225, A001221, A065341, A054723, A134852.
%K nonn
%O 1,1
%A _Artur Jasinski_, Dec 09 2007
%E a(29)-a(46) from _Felix Fröhlich_, Aug 12 2014
%E a(47)-a(100) from _Gord Palameta_, Aug 07 2018
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