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 A030780 #11 Apr 09 2020 00:51:55 %S A030780 2,3,1,14,10,8,13,20,22,29,40,31,54,190,42,68,85,55,122,146,70,170, %T A030780 169,87,227,195,106,225,226,126,261,148,299,172,228,526,199,340,585, %U A030780 263,229,301,530,264,430,776,710,342,479,302,532,386,531,343,432,1749 %N A030780 a(n) is the least k such that A030777(k) = n. %Y A030780 Cf. A030777. %K A030780 nonn %O A030780 1,1 %A A030780 _Clark Kimberling_ %E A030780 Name clarified by _Jinyuan Wang_, Apr 08 2020 %E A030780 More terms from _Sean A. Irvine_, Apr 08 2020