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A353707
n appears in A121216 a(n) steps earlier than expected.
3
0, 0, 0, -1, 1, 0, 0, -1, -1, -2, 3, -1, 2, -2, -2, -3, 3, -2, 4, -3, 0, -2, 5, -4, 3, -1, 2, -3, 3, -6, 2, 0, 0, -1, 5, -4, 3, -1, 2, -3, 3, -2, 2, -3, -3, -4, 5, -6, 4, -1, 2, -3, 7, -4, 3, -3, 4, -4, 3, -3, 4, -4, -1, -3, 5, -5, 6
OFFSET
1,10
COMMENTS
It appears that a positive number n appears in A121216 at about the n-th term; if in fact A121216(k) = n, then a(n) = n - k.
An equivalent definition uses the inverse to A121216: a(n) = n - A225047(n).
LINKS
Rémy Sigrist, PARI program
EXAMPLE
A121216(8) = 11, so 11 has appeared 3 steps early, therefore a(11) = 11 - 8 = 3.
PROG
(PARI) See Links section.
CROSSREFS
KEYWORD
sign
AUTHOR
N. J. A. Sloane, May 05 2022
STATUS
approved