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 A020949 #3 Mar 30 2012 18:55:50 %S A020949 1,4,11,10,20,24,22,42,89,44,46,84,100,88,96,90,92,204,170,202,192, %T A020949 190,178,184,180,188,186,338,382,340,366,354,358,390,360,356,376,364, %U A020949 674,362,378,680,372,676,684,710,812,682,752,708,810,1346,732 %N A020949 Least k such that A(k) = n, where A( ) is sequence A020945. %Y A020949 Cf. A020943-A020945, A002487, A020947-A020950. %K A020949 nonn %O A020949 1,2 %A A020949 _Clark Kimberling_