A269968 - OEIS

A269968

Index of first occurrence of n in A269783.

0, 2, 8, 12, 25, 32, 36, 60, 71, 76, 80, 119, 134, 143, 148, 152, 210, 231, 242, 249, 254, 258, 339, 366, 381, 392, 399, 404, 408, 516, 549, 568, 581, 590, 597, 602, 606, 745, 786, 811, 826, 839, 848, 855, 860, 864, 1038, 1085, 1114, 1135, 1150, 1161, 1170

(list; graph; refs; listen; history; text; internal format)

OFFSET

0,2

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

PROG

(PARI) See Links section.

CROSSREFS

Cf. A269783 (main sequence), A269967 (indices of zeros), A269969 (index of first occurrence of -n).

Sequence in context: A359964 A277804 A108978 * A135957 A107755 A268836

Adjacent sequences: A269965 A269966 A269967 * A269969 A269970 A269971

KEYWORD

nonn

AUTHOR

M. F. Hasler, Mar 08 2016

EXTENSIONS

More terms from Rémy Sigrist, May 21 2023

STATUS

approved