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A157588 Half the number of length n integer sequences with sum zero and sum of squares 6272. 1

%I

%S 1,9,54,18490,3080025,281083131,20455480647,1378645284663,

%T 90798695826120,5747081242763245,353783429708291517,

%U 21210677666294419836,1217797507802900629878,66543379957754376544455

%N Half the number of length n integer sequences with sum zero and sum of squares 6272.

%H R. H. Hardin, <a href="/A157588/b157588.txt">Table of n, a(n) for n=2..50</a>

%F [cache enabling] count(n,s,ss)->count(n,t,tt) where t=s mod n, q=(t-s)/n, tt=ss+2*q*s+n*q^2; count(n,t,tt)=sum[i^2<=tt]{ count(n-1,t-i,tt-i^2) }. a(n)=count(n,0,6272)/2.

%K nonn

%O 2,2

%A _R. H. Hardin_ Mar 02 2009

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Last modified September 29 22:48 EDT 2022. Contains 357092 sequences. (Running on oeis4.)