%I #4 Mar 31 2012 12:35:25
%S 1,3,306,19110,1405335,127596189,10056226796,714714066732,
%T 47739604854315,2926869332706055,164336205885920178,
%U 8620987583406297606,434508999474316043459,21294115220098361584440,1014206441760046027667880
%N Half the number of length n integer sequences with sum zero and sum of squares 5202.
%H R. H. Hardin, <a href="/A157583/b157583.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,0,5202)/2.
%K nonn
%O 2,2
%A _R. H. Hardin_ Mar 02 2009