%I A157597
%S A157597 1,9,630,48670,4293525,358348053,32224041500,2966406894648,
%T A157597 259556693304825,20157653282906667,1439903350550159550,
%U A157597 97064374251531230622,6271845201623139087495,391742584864070048279685
%N A157597 Half the number of length n integer sequences with sum zero and sum of 
               squares 8450.
%H A157597 Ron Hardin, <a href="b157597.txt">Table of n, a(n) for n=2..50</a>
%F A157597 [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,0,8450)/2.
%Y A157597 Sequence in context: A139107 A085530 A158881 this_sequence A128795 A081232 
               A020548
%Y A157597 Adjacent sequences: A157594 A157595 A157596 this_sequence A157598 A157599 
               A157600
%K A157597 nonn
%O A157597 2,2
%A A157597 Ron Hardin (rhhardin(AT)att.net) Mar 02 2009