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 A030498 #7 Apr 02 2020 18:05:23 %S A030498 2,5,7,11,12,15,20,22,26,31,33,37,43,46,50,55,57,61,67,70,72,76,80,84, %T A030498 88,92,99,102,107,110,113,117,123,129,132,137,144,148,153,159,162,167, %U A030498 174,178,181,186,191,196,201,206,214,218,224,228,232,237,243,249 %N A030498 Position of n-th 2 in A030496. %K A030498 nonn %O A030498 1,1 %A A030498 _Clark Kimberling_ %E A030498 a(33) onward corrected by _Sean A. Irvine_, Apr 02 2020