%I
%S 1,3,66,14630,1446495,105717843,6111518987,323657828739,
%T 16777260176400,835056998169955,40377792647031081,1902059925519314067,
%U 85804943707548960986,3683698658760163764945,151229533594426205964390
%N Half the number of length n integer sequences with sum zero and sum of squares 3872.
%H R. H. Hardin, <a href="/A157576/b157576.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=(ts)/n, tt=ss+2*q*s+n*q^2; count(n,t,tt)=sum[i^2<=tt]{ count(n1,ti,tti^2) }. a(n)=count(n,0,3872)/2.
%K nonn
%O 2,2
%A _R. H. Hardin_ Mar 02 2009
