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 A090658 #10 Sep 25 2017 15:50:39
%S A090658 4,8,12,20,24,32,44,48,60,68,72,80,84,104,108,128,132,140,152,164,168,
%T A090658 180,192,200,212,224,228,240,252,264,272,284,308,312,332,348,360,368,
%U A090658 380,384,420,432,440,444,464,468,480,488,492,500,504,524,548,564,572
%N A090658 Numbers n such that n-1 is a prime of the form 4k+3.
%D A090658 M. Cerasoli, F. Eugeni and M. Protasi, Elementi di Matematica Discreta, Bologna 1988
%D A090658 Emanuele Munarini and Norma Zagaglia Salvi, Matematica Discreta,UTET, CittaStudiEdizioni, Milano 1997
%H A090658 Vincenzo Librandi, <a href="/A090658/b090658.txt">Table of n, a(n) for n = 1..5000</a>
%F A090658 a(n) = A087915(n)+A089257(n), A089193(n)+A089257(n)-5.
%t A090658 okQ[n_]:=Module[{x=n-1},PrimeQ[x]&&IntegerQ[(x-3)/4]];Select[Range[1,1000,1],okQ] (* _Vincenzo Librandi_, Dec 13 2011 *)
%t A090658 Select[4*Range[0,200]+3,PrimeQ]+1 (* _Harvey P. Dale_, Sep 25 2017 *)
%Y A090658 Cf. A002145, A087915, A089193, A089257.
%K A090658 easy,nonn
%O A090658 1,1
%A A090658 _Giovanni Teofilatto_, Dec 14 2003
%E A090658 Corrected and extended by _T. D. Noe_, Oct 25 2006