%I #11 Sep 08 2022 08:46:08
%S 1,2,3,4,8,9,14,18,21,22,24,26,27,28,30,33,42,44,51,54,57,58,62,63,64,
%T 68,69,82,84,86,90,93,98,99,102,104,108,111,118,132,134,138,144,152,
%U 154,156,166,174,177,180,183,184,186,188,189,194,208,210,212,216
%N Numbers k such that k^2 + 5 is a semiprime.
%C The semiprimes of this form are: 6, 9, 14, 21, 69, 86, 201, 329, 446, 489, 581, 681, 734, 789, 905, 1094, 1769, 1941, 2606, 2921, 3254, ...
%H Vincenzo Librandi, <a href="/A242333/b242333.txt">Table of n, a(n) for n = 1..1000</a>
%t Select[Range[0, 300], PrimeOmega[#^2 + 5] == 2 &]
%o (Magma) IsSemiprime:=func<i | &+[d[2]: d in Factorization(i)] eq 2>; [n: n in [0..300] | IsSemiprime(s) where s is n^2+5];
%Y Cf. A056905, A078402, A085722, A242330, A242331, A242332.
%K nonn,easy
%O 1,2
%A _Vincenzo Librandi_, May 14 2014
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