%I #4 Mar 31 2012 12:35:25
%S 1,3,330,27570,2233965,165759111,11709395180,864416336904,
%T 61700500723635,3932420281395045,229474040212588578,
%U 12613127103936869874,664285970637825836755,33831654295810674426165,1673010760008675643666440
%N Half the number of length n integer sequences with sum zero and sum of squares 5618.
%H R. H. Hardin, <a href="/A157585/b157585.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,0,5618)/2.
%K nonn
%O 2,2
%A _R. H. Hardin_ Mar 02 2009