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%I #9 Aug 10 2021 03:33:00
%S 2,11,29,157,113,223,491,431,397
%N Smallest prime p such that the Mersenne number A000225(p) = 2^p - 1 has exactly n prime factors (counted with multiplicity).
%D J.-M. De Koninck, Ces nombres qui nous fascinent, Entry 223, pp 63-4, Ellipse Paris 2008.
%o (PARI) a(n) = forprime(p=2, oo, if(bigomega(2^p-1)==n, return(p))); \\ _Jinyuan Wang_, Aug 10 2021
%Y Cf. A000225, A001222, A046051, A136033.
%K nonn,more
%O 1,1
%A _Lekraj Beedassy_, Jul 12 2008
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