This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A242332 #14 Sep 08 2022 08:46:08 %S A242332 0,9,19,21,23,25,31,41,43,51,53,55,63,69,71,75,77,79,83,91,93,105,107, %T A242332 109,113,119,123,129,131,133,143,145,149,151,153,157,165,171,173,175, %U A242332 181,185,187,191,195,197,201,209,221,223,225,227,241,249,251,257,259 %N A242332 Numbers k such that k^2 + 4 is a semiprime. %C A242332 The semiprimes of this form are: 4, 85, 365, 445, 533, 629, 965, 1685, 1853, 2605, 2813, 3029, 3973, 4765, 5045, 5629, 5933, 6245, ... %H A242332 Vincenzo Librandi, <a href="/A242332/b242332.txt">Table of n, a(n) for n = 1..1000</a> %t A242332 Select[Range[0, 300], PrimeOmega[#^2 + 4] == 2 &] %o A242332 (Magma) IsSemiprime:=func<i | &+[d[2]: d in Factorization(i)] eq 2>; [n: n in [0..300] | IsSemiprime(s) where s is n^2+4]; %Y A242332 Cf. A005473, A007591, A085722, A242330, A242331, A242333. %K A242332 nonn %O A242332 1,2 %A A242332 _Vincenzo Librandi_, May 14 2014