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A322538 Number of arrays of n integers in -8..8 with sum zero. 2
1, 1, 17, 217, 3281, 50101, 782153, 12354469, 197018321, 3164588407, 51125645317, 829858058019, 13522838817929, 221088393889403, 3624855419439957, 59576725303913167, 981272544393935569, 16192709833199300337, 267654541150392845543, 4430755975190532983531 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

LINKS

Seiichi Manyama, Table of n, a(n) for n = 0..350

FORMULA

a(n) = [x^(8*n)] (Sum_{k=0..16} x^k)^n.

a(n) ~ 17^n / (4*sqrt(3*Pi*n)). - Vaclav Kotesovec, Dec 15 2018

MATHEMATICA

a[n_] := If[n==0, 1, Coefficient[Expand[Sum[x^k, {k, 0, 16}]^n], x^(8n)]]; Array[a, 25, 0] (* Amiram Eldar, Dec 14 2018 *)

PROG

(PARI) {a(n) = polcoeff((sum(k=0, 16, x^k))^n, 8*n, x)}

CROSSREFS

Column 8 of A201552.

Sequence in context: A139733 A016185 A125452 * A016238 A016181 A285233

Adjacent sequences: A322535 A322536 A322537 * A322539 A322540 A322541

KEYWORD

nonn

AUTHOR

Seiichi Manyama, Dec 14 2018

STATUS

approved

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Last modified February 3 17:00 EST 2023. Contains 360044 sequences. (Running on oeis4.)