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A322538
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Number of arrays of n integers in -8..8 with sum zero.
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2
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1, 1, 17, 217, 3281, 50101, 782153, 12354469, 197018321, 3164588407, 51125645317, 829858058019, 13522838817929, 221088393889403, 3624855419439957, 59576725303913167, 981272544393935569, 16192709833199300337, 267654541150392845543, 4430755975190532983531
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OFFSET
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0,3
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LINKS
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Seiichi Manyama, Table of n, a(n) for n = 0..350
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FORMULA
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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
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MATHEMATICA
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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 *)
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PROG
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(PARI) {a(n) = polcoeff((sum(k=0, 16, x^k))^n, 8*n, x)}
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CROSSREFS
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Column 8 of A201552.
Sequence in context: A139733 A016185 A125452 * A016238 A016181 A285233
Adjacent sequences: A322535 A322536 A322537 * A322539 A322540 A322541
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KEYWORD
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nonn
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AUTHOR
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Seiichi Manyama, Dec 14 2018
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STATUS
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approved
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