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 A030755 #9 Feb 12 2021 17:48:47 %S A030755 5,7,14,21,37,48,61,90,111,129,179,202,205,208,228,233,239,269,272, %T A030755 308,340,341,343,346,386,430,465,473,478,519,524,529,576,579,582,639, %U A030755 698,753,761,814,821,824,828,890,899 %N A030755 Numbers k such that A030747(k) = 3. %K A030755 nonn %O A030755 1,1 %A A030755 _Clark Kimberling_ %E A030755 Corrected by _Franklin T. Adams-Watters_, Oct 25 2006