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 A169850 #6 Jun 04 2022 21:53:05 %S A169850 4,2,5,8,3,12,6,1,7,18,10,22,11,9,15,31,14,35,16,13,17,41,20,26,21,24, %T A169850 28,56,25,60,29,19,30,27,33,66,34,23,38,73,37,80,39,43,40,88,44,49,45, %U A169850 32,46,99,47,52,48,36,55,106,51,114,59,50,63,53,58,127,64,42,54,133,62,137,65 %N A169850 a(n) = position of n in A169849. %C A169850 A generalization of A064421. %K A169850 nonn %O A169850 2,1 %A A169850 _T. D. Noe_ and _N. J. A. Sloane_, Jun 02 2010