%I A157588
%S A157588 1,9,54,18490,3080025,281083131,20455480647,1378645284663,90798695826120,
%T A157588 5747081242763245,353783429708291517,21210677666294419836,
%U A157588 1217797507802900629878,66543379957754376544455
%N A157588 Half the number of length n integer sequences with sum zero and sum of 
               squares 6272.
%H A157588 Ron Hardin, <a href="b157588.txt">Table of n, a(n) for n=2..50</a>
%F A157588 [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,0,6272)/2.
%Y A157588 Sequence in context: A157539 A157546 A157560 this_sequence A058849 A058852 
               A145875
%Y A157588 Adjacent sequences: A157585 A157586 A157587 this_sequence A157589 A157590 
               A157591
%K A157588 nonn
%O A157588 2,2
%A A157588 Ron Hardin (rhhardin(AT)att.net) Mar 02 2009