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 A269967 #11 May 21 2023 08:25:01 %S A269967 0,1,4,7,15,23,40,55,85,111,158,197,265,323,416,493,615,719,874,1005, %T A269967 1197,1361,1594,1793,2071,2313,2640,2921,3301,3633,4070,4453,4951, %U A269967 5389,5952,6447,7079,7641,8346,8971,9753,10453,11316,12087,13035,13885,14922 %N A269967 Indices of zeros in A269783. %C A269967 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 A269967 Rémy Sigrist, <a href="/A269967/b269967.txt">Table of n, a(n) for n = 1..10000</a> %H A269967 Rémy Sigrist, <a href="/A269967/a269967.txt">C++ program</a> %o A269967 (C++) See Links section. %Y A269967 Cf. A269783 (main sequence), A269968 (index of first occurrence of n), A269969 (index of first occurrence of -n). %K A269967 nonn %O A269967 1,3 %A A269967 _M. F. Hasler_, Mar 08 2016 %E A269967 More terms from _Rémy Sigrist_, May 21 2023