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 A190450 #4 Mar 30 2012 18:57:28 %S A190450 3,8,16,21,29,37,42,50,55,58,63,71,76,84,92,97,105,110,118,126,131, %T A190450 139,144,147,152,160,165,173,181,186,194,199,207,215,220,228,236,241, %U A190450 249,254,262,270,275,283,288,291,296,304,309,317,325,330,338,343,351,359,364,372,377,380,385,393,398,406 %N A190450 Positions of 4 in A190445. %C A190450 See A190445. %t A190450 (See A190445.) %Y A190450 Cf. A190445. %K A190450 nonn %O A190450 1,1 %A A190450 _Clark Kimberling_, May 10 2011