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 A269968 #15 May 21 2023 08:24:46
%S A269968 0,2,8,12,25,32,36,60,71,76,80,119,134,143,148,152,210,231,242,249,
%T A269968 254,258,339,366,381,392,399,404,408,516,549,568,581,590,597,602,606,
%U A269968 745,786,811,826,839,848,855,860,864,1038,1085,1114,1135,1150,1161,1170
%N A269968 Index of first occurrence of n in A269783.
%C A269968 Sequence A269783 is defined by A269783(0)=0 and A269783(n+1) = A269783(n) + (-1)^(k+e)*floor(k/2), where k = #{ j<=n | A269783(j)=A269783(n) } and e=1 for A269783(n)>0, else e=0. That is, the 1st, 2nd, 3rd, 4th... occurrence of any positive integer n is followed by n resp. n-1 resp. n+1 resp. n-2, etc., and for zero or negative integers the same with opposite sign.
%H A269968 Rémy Sigrist, <a href="/A269968/b269968.txt">Table of n, a(n) for n = 0..10000</a>
%H A269968 Rémy Sigrist, <a href="/A269968/a269968.gp.txt">PARI program</a>
%o A269968 (PARI) See Links section.
%Y A269968 Cf. A269783 (main sequence), A269967 (indices of zeros), A269969 (index of first occurrence of -n).
%K A269968 nonn
%O A269968 0,2
%A A269968 _M. F. Hasler_, Mar 08 2016
%E A269968 More terms from _Rémy Sigrist_, May 21 2023