A157586 - OEIS

%I #4 Mar 31 2012 12:35:25

%S 1,3,162,16410,1839645,210928977,17676193171,1148671947972,

%T 71262995700540,4352863891098140,258238261126722129,

%U 14806140740844716211,815211282605034375060,42951699550186642926270,2166061193994862365099390

%N Half the number of length n integer sequences with sum zero and sum of squares 5832.

%H R. H. Hardin, <a href="/A157586/b157586.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,0,5832)/2.

%K nonn

%O 2,2

%A _R. H. Hardin_ Mar 02 2009