%I #4 Mar 31 2012 12:35:25
%S 1,3,222,23430,2211435,165640041,11463980983,700674124347,
%T 41384377023300,2326405435793384,127560765651968055,
%U 6827700441824422953,350130844722624976920,17081201454932094454170,796830250007891403178002
%N Half the number of length n integer sequences with sum zero and sum of squares 5000.
%H R. H. Hardin, <a href="/A157582/b157582.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,0,5000)/2.
%K nonn
%O 2,2
%A _R. H. Hardin_ Mar 02 2009