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 A112771 #20 Sep 08 2022 08:45:23 %S A112771 25,49,55,85,91,115,121,133,145,169,187,205,217,235,247,253,259,265, %T A112771 289,295,301,319,355,361,391,403,415,427,445,451,469,481,493,505,511, %U A112771 517,529,535,553,559,565,583,589,649,655,667,679,685,697,703,721,745 %N A112771 Semiprimes of the form 6n + 1. %C A112771 Union of A108164 and A108166. %C A112771 Subsequence of A091300. - _Zak Seidov_, Dec 28 2015 %H A112771 Vincenzo Librandi, <a href="/A112771/b112771.txt">Table of n, a(n) for n = 1..1000</a> %F A112771 a(n) = 6 * A112775(n) +1. %t A112771 Select[6 Range[0, 200] + 1, PrimeOmega[#] == 2&] (* _Vincenzo Librandi_, Sep 22 2012 *) %o A112771 (Magma) IsSemiprime:=func<n | &+[d[2]: d in Factorization(n)] eq 2>; [s: n in [2..150] | IsSemiprime(s) where s is 6*n + 1]; // _Vincenzo Librandi_, Sep 22 2012 %K A112771 easy,nonn %O A112771 1,1 %A A112771 _Jonathan Vos Post_ and _Ray Chandler_, Oct 15 2005