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 A090161 #9 Aug 06 2021 07:06:02 %S A090161 3,4,5,6,8,10,12,13,15,16,18,22,23,25,27,28,30,31,32,33,34,35,36,38, %T A090161 42,44,45,47,50,51,52,55,56,58,62,65,69,72,74,75,77,79,82,83,86,87,89, %U A090161 91,93,96,97,99,100,101,102,104,105,108,109,110,111,117,119,120,122,123 %N A090161 A023219 indexed by A000040. %F A090161 a(n) = k such that A000040(k) = A023219(n). %F A090161 a(n) = A000720(A023219(n)). - _Michel Marcus_, Aug 06 2021 %Y A090161 Cf. A023219, A088555, A088561. %K A090161 nonn,easy %O A090161 1,1 %A A090161 _Ray Chandler_, Nov 28 2003 %E A090161 Offset changed to 1 by _Jinyuan Wang_, Aug 06 2021