%I A157599
%S A157599 1,9,402,44230,4512465,423267831,37803628716,3527887213476,
%T A157599 318332583745245,25647872392849575,1892012326768856754,
%U A157599 131465592083214083058,8752726227773492626389,563521423775802944905950
%N A157599 Half the number of length n integer sequences with sum zero and sum of 
               squares 8978.
%H A157599 Ron Hardin, <a href="b157599.txt">Table of n, a(n) for n=2..50</a>
%F A157599 [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,0,8978)/2.
%Y A157599 Sequence in context: A124042 A012191 A012078 this_sequence A063876 A063156 
               A058850
%Y A157599 Adjacent sequences: A157596 A157597 A157598 this_sequence A157600 A157601 
               A157602
%K A157599 nonn
%O A157599 2,2
%A A157599 Ron Hardin (rhhardin(AT)att.net) Mar 02 2009