%I #4 Mar 31 2012 12:35:25
%S 1,3,42,13330,1149525,68923281,3762973571,184036492377,8678968080840,
%T 390210773279547,17118756925603575,733096379424490302,
%U 30076017737894907870,1173815703627064565445,43806372065182513944702
%N Half the number of length n integer sequences with sum zero and sum of squares 3200.
%H R. H. Hardin, <a href="/A157572/b157572.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,0,3200)/2.
%K nonn
%O 2,2
%A _R. H. Hardin_ Mar 02 2009