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 A074381 #9 Jul 29 2017 23:48:53 %S A074381 1,0,1,0,0,0,1,1,0,1,0,0,1,1,0,1,1,0,0,1,1,1,1,0,0,0,1,0,0,1,0,0,1,0, %T A074381 0,1,1,0,0,1,1,0,0,0,0,1,1,1,0,1,1,1,1,0,0,1,1,0,1,0,0,1,0,1,1,0,0,0, %U A074381 1,0,1,0,0,1,0,1,1,0,0,0,0,1,1,1,1,0,1,0,1,1,0,0,1,1,1,0,0,1,1,0,1,0,0,0,1 %N A074381 (p-1)/2 mod 2, where p is the n-th prime for which p+2 is also prime; i.e., a(n)=0 if p==1 (mod 4), a(n)=1 if p==3 (mod 4). %t A074381 Mod[(Select[Prime/@Range[600], PrimeQ[ #+2]&]-1)/2, 2] %Y A074381 Cf. A001359, A071695, A071698. %K A074381 nonn,easy %O A074381 1,1 %A A074381 _Roger L. Bagula_, Sep 24 2002 %E A074381 Edited by _Dean Hickerson_ and _Robert G. Wilson v_, Oct 09 2002