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 A022305 #3 Mar 30 2012 18:55:50 %S A022305 2,4,6,10,12,14,16,18,20,22,24,26,32,34,36,38,40,42,44,46,50,52,54,56, %T A022305 58,60,64,66,68,70,72,74,76,78,82,84,94,100,102,112,114,118,120,122, %U A022305 124,126,128,132,134,136,138,140,142,144,146,148,154,156,158 %N A022305 Exactly half the first a(n) terms of A022303 are 1's. %K A022305 nonn %O A022305 0,1 %A A022305 _Clark Kimberling_