A269969 - OEIS

%I #15 May 21 2023 08:24:35

%S 0,5,16,20,42,47,51,88,97,102,106,164,175,182,187,191,274,289,300,307,

%T 312,316,428,447,460,469,476,481,485,632,657,672,685,694,701,706,710,

%U 894,923,944,959,970,979,986,991,995,1222,1257,1282,1299,1314,1325,1334

%N Index of first occurrence of -n in A269783.

%C 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 Rémy Sigrist, <a href="/A269969/b269969.txt">Table of n, a(n) for n = 0..10000</a>

%H Rémy Sigrist, <a href="/A269969/a269969.gp.txt">PARI program</a>

%o (PARI) See Links section.

%Y Cf. A269783 (main sequence), A269967 (indices of zeros), A269968 (index of first occurrence of n).

%K nonn

%O 0,2

%A _M. F. Hasler_, Mar 08 2016

%E More terms from _Rémy Sigrist_, May 21 2023