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%I #21 Dec 11 2024 04:56:00
%S 7,8,12,23,65,67,76,81,87,90,92,93,95,121,123,143,146,161,181,203,218,
%T 220,235,241,251,252,287,321,330,388,406,423,437,438,443,455,456,507,
%U 555,594,603,626,646,661,665,672,685,707,708,715,720,755,808,837,856
%N Numbers k such that the k-th partition number (A000041(k)) is a semiprime.
%H Harry J. Smith, <a href="/A065729/b065729.txt">Table of n, a(n) for n = 1..100</a>
%H Hisanori Mishima, <a href="http://www.asahi-net.or.jp/~KC2H-MSM/mathland/matha1/index.htm">Factorization results</a>
%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/Semiprime.html">Semiprime.</a>
%e The 808th partition number 8151756509675604512522473567 = 5963320232189 * 1366982853893003.
%t Select[Range[900],PrimeOmega[PartitionsP[#]]==2&] (* _Harvey P. Dale_, Nov 27 2024 *)
%o (PARI) isok(k) = { bigomega(numbpart(k))==2 } \\ _Harry J. Smith_, Oct 28 2009
%Y Cf. A000041, A001358, A049575, A065728.
%K nonn,changed
%O 1,1
%A _Patrick De Geest_, Nov 18 2001
%E Offset changed from 0 to 1 by _Harry J. Smith_, Oct 28 2009
%E Missing a(38) = 507 added by _Harry J. Smith_, Oct 28 2009