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 A024978 #7 Jul 31 2019 07:18:13 %S A024978 2,4,6,9,11,13,14,16,18,21,23,25,27,29,30,33,35,36,39,40,42,45,46,49, %T A024978 50,54,56,57,60,61,64,66,69,71,72,74,76,78,79,81,84,85,86,89,90,94,96, %U A024978 98,99,103,104,106,109,110,112,114,115,119,120,122,124,127,130,131,132,134,136,138 %N A024978 Positions of odd numbers in A024975. %K A024978 nonn %O A024978 1,1 %A A024978 _Clark Kimberling_ %E A024978 a(68) corrected by _Sean A. Irvine_, Jul 31 2019