A269969 Index of first occurrence of -n in A269783.

0, 5, 16, 20, 42, 47, 51, 88, 97, 102, 106, 164, 175, 182, 187, 191, 274, 289, 300, 307, 312, 316, 428, 447, 460, 469, 476, 481, 485, 632, 657, 672, 685, 694, 701, 706, 710, 894, 923, 944, 959, 970, 979, 986, 991, 995, 1222, 1257, 1282, 1299, 1314, 1325, 1334

Offset: 0

Author

M. F. Hasler, Mar 08 2016

Keywords

• nonn

Comments

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.

Links

• Rémy Sigrist, Table of n, a(n) for n = 0..10000
• Rémy Sigrist, PARI program

Crossrefs

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

Programs

PARI

See Links section.

Extensions

More terms from Rémy Sigrist, May 21 2023