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 A166236 #7 Sep 17 2017 21:41:39
%S A166236 1,2,4,5,6,5,7,6,5,7,6,5,6,5,5,3,4,4,3,4,3,2,1,2,3,2,1,1,1,5,6,8,8,12,
%T A166236 11,12,14,13,15,17,17,19,19,19,19,23,27,28,27,28,28,28,32,34,34,34,34,
%U A166236 36,37,37,40,46,47,47,48,53,53,56,56,55,57,60,62,63,64,65,68,68,71,73
%N A166236 Absolute value of (n-th odd prime minus n-th odd nonprime)/2.
%H A166236 G. C. Greubel, <a href="/A166236/b166236.txt">Table of n, a(n) for n = 1..5000</a>
%F A166236 a(n) = abs(A065091(n) - A014076(n))/2.
%e A166236 a(1)=abs(3-1)/2=1; a(2)=abs(5-9)/2=abs(-2)=2; a(3)=abs(7-15)/2=abs(-4)=4.
%t A166236 A014076 := Select[Range@500, ! PrimeQ@# && OddQ@# &]; A065091 := Prime[Range[2, 500]]; Table[Abs[A065091[[n]] - A014076[[n]]]/2, {n, 1, 50}] (* _G. C. Greubel_, Sep 17 2017 *)
%Y A166236 Cf. A014076, A065091.
%K A166236 nonn
%O A166236 1,2
%A A166236 _Juri-Stepan Gerasimov_, Oct 09 2009
%E A166236 Entries checked by _R. J. Mathar_, May 21 2010