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 A026229 #14 Jul 04 2021 13:45:00 %S A026229 2,6,12,18,21,30,36,39,48,54,57,63,66,75,84,90,93,102,108,111,117,120, %T A026229 129,138,144,147,156,162,165,171,174,183,189,192,198,201,210,219,225, %U A026229 228,237,246,252,255,264,270,273,279,282,291 %N A026229 Numbers k such that A026166(k) = A026142(k) - 2. %Y A026229 Cf. A026142, A026166. %K A026229 nonn %O A026229 1,1 %A A026229 _Clark Kimberling_ %E A026229 Title corrected by _Sean A. Irvine_, Sep 22 2019