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

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), A269969 (index of first occurrence of -n).

Programs

PARI

See Links section.

Extensions

More terms from Rémy Sigrist, May 21 2023