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 A026415 #14 Jul 04 2021 13:30:05 %S A026415 1,3,6,7,9,11,12,16,17,19,22,24,25,26,27,32,33,35,36,38,41,44,45,48, %T A026415 49,50,53,54,55,58,60,61,62,67,70,71,74,75,76,80,84,85,86,87,88,89,91, %U A026415 96,99,101,102,104,105,107,108,112,114,117,118,120,121,124,127,128,129,132 %N A026415 Numbers k such that A026409(k) is odd. %Y A026415 Cf. A026409. %K A026415 nonn %O A026415 1,2 %A A026415 _Clark Kimberling_ %E A026415 More terms from _Sean A. Irvine_, Sep 26 2019