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A322535 Number of arrays of 8 integers in -n..n with sum zero. 2

%I

%S 1,1107,38165,398567,2306025,9377467,30162301,82073295,197018321,

%T 429042211,864287973,1633586615,2927984825,5017519755,8273550157,

%U 13194953119,20438495649,30853690355,45522444469,65803811463,93384154505,130333031003,179165107485,242908414063

%N Number of arrays of 8 integers in -n..n with sum zero.

%H Seiichi Manyama, <a href="/A322535/b322535.txt">Table of n, a(n) for n = 0..10000</a>

%F a(n) = [x^(8*n)] (Sum_{k=0..2*n} x^k)^8.

%F a(n) = (2*n+1)*(9664*n^6+28992*n^5+37360*n^4+26400*n^3+10936*n^2+2568*n+315)/315.

%t a[n_] := Coefficient[Expand[Sum[x^k, {k, 0, 2n}]^8, x], x, 8n]; Array[a, 25, 0] (* _Amiram Eldar_, Dec 14 2018 *)

%o (PARI) {a(n) = polcoeff((sum(k=0, 2*n, x^k))^8, 8*n, x)}

%Y Row 8 of A201552.

%K nonn

%O 0,2

%A _Seiichi Manyama_, Dec 14 2018

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Last modified January 27 21:49 EST 2023. Contains 359849 sequences. (Running on oeis4.)