%I #4 Mar 31 2012 12:35:25
%S 1,9,234,13330,759255,39386151,1941592492,100065421116,4986199986795,
%T 221853806154915,9037873481632974,346801773380423010,
%U 12750860059402207015,453349862010556020825,15650738757439717731720
%N Half the number of length n integer sequences with sum zero and sum of squares 2738.
%H R. H. Hardin, <a href="/A157569/b157569.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,0,2738)/2.
%K nonn
%O 2,2
%A _R. H. Hardin_ Mar 02 2009
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