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%I #4 Mar 31 2012 12:35:25
%S 1,3,294,21630,1556655,102426933,6421722076,420393758436,
%T 26609856588945,1503958534048245,77827209776501394,
%U 3793522397195559678,177172760525971961023,8001788984919141620040,350900981113969220953080
%N Half the number of length n integer sequences with sum zero and sum of squares 4418.
%H R. H. Hardin, <a href="/A157579/b157579.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,0,4418)/2.
%K nonn
%O 2,2
%A _R. H. Hardin_ Mar 02 2009
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