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 A085199 #6 Jan 12 2024 10:59:50 %S A085199 0,1,0,2,0,3,0,0,0,4,0,5,0,0,0,6,0,7,0,0,0,0,0,8,0,0,0,0,0,0,0,0,0,9, %T A085199 0,10,0,0,0,11,0,12,0,0,0,0,0,13,0,0,0,0,0,0,0,0,0,14,0,15,0,0,0,16,0, %U A085199 17,0,0,0,0,0,18,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,19,0,20,0,0,0,0,0,21,0,0,0 %N A085199 Inverse function of N -> N injection A071156. %C A085199 a(0)=0 because A071156(0)=0, but a(n) = 0 also for those n which do not occur as values of A071156. All positive natural numbers occur here once. %F A085199 a(n) = A057164(A085200(n)). %Y A085199 a(A071156(n)) = n for all n. %K A085199 nonn %O A085199 0,4 %A A085199 _Antti Karttunen_, Jun 14 2003