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%I #4 Mar 31 2012 12:35:25
%S 1,9,114,11430,928665,57312801,2929653363,133959064275,6012597282660,
%T 258520740868390,10793900036914731,439085564014381089,
%U 17106142080255638592,634240156516816014270,22487281301691416873070
%N Half the number of length n integer sequences with sum zero and sum of squares 2888.
%H R. H. Hardin, <a href="/A157570/b157570.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,0,2888)/2.
%K nonn
%O 2,2
%A _R. H. Hardin_ Mar 02 2009
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