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 A322536 Number of arrays of 9 integers in -n..n with sum zero. 2

%I

%S 1,3139,180325,2636263,19610233,97464799,370487485,1163205475,

%T 3164588407,7702189345,17148949027,35500063501,69161990275,

%U 128000343121,226698100687,386480229085,637265493637,1020310909975,1591418959705,2424782370859,3617545938373,5295169534843

%N Number of arrays of 9 integers in -n..n with sum zero.

%H Seiichi Manyama, <a href="/A322536/b322536.txt">Table of n, a(n) for n = 0..10000</a>

%F a(n) = [x^(9*n)] (Sum_{k=0..2*n} x^k)^9.

%t a[n_] := Coefficient[Expand[Sum[x^k, {k, 0, 2n}]^9, x], x, 9n]; Array[a, 25, 0] (* _Amiram Eldar_, Dec 14 2018 *)

%o (PARI) {a(n) = polcoeff((sum(k=0, 2*n, x^k))^9, 9*n, x)}

%Y Row 9 of A201552.

%K nonn

%O 0,2

%A _Seiichi Manyama_, Dec 14 2018

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Last modified March 25 07:51 EDT 2023. Contains 361511 sequences. (Running on oeis4.)