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 A030499 #7 Apr 02 2020 18:02:59 %S A030499 6,9,13,17,19,23,25,29,34,39,42,47,48,52,56,60,64,68,74,79,81,85,91, %T A030499 94,98,103,105,109,115,118,122,127,133,139,143,149,151,156,161,166, %U A030499 171,176,183,189,192,197,204,208,213,219,222,227,234,238,242,247,253 %N A030499 Position of n-th 3 in A030496. %K A030499 nonn %O A030499 1,1 %A A030499 _Clark Kimberling_ %E A030499 a(31) onward corrected by _Sean A. Irvine_, Apr 02 2020