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%I #4 Mar 31 2012 12:35:25
%S 1,3,378,18910,992325,74527005,5338966892,339980231676,20037272191665,
%T 1077068920503015,53256851208061050,2465137614876120834,
%U 109671118311748056245,4742369931941953806600,199288535032516918383432
%N Half the number of length n integer sequences with sum zero and sum of squares 4050.
%H R. H. Hardin, <a href="/A157577/b157577.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,0,4050)/2.
%K nonn
%O 2,2
%A _R. H. Hardin_ Mar 02 2009
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