|
%I #4 Mar 31 2012 12:35:25
%S 1,9,486,26230,2658825,303936255,29022562044,2546840675268,
%T 209628417451815,15863225333113455,1100628488842991790,
%U 71323826984704710078,4440654868991991482287,268844012960749492143465
%N Half the number of length n integer sequences with sum zero and sum of squares 7938.
%H R. H. Hardin, <a href="/A157595/b157595.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,0,7938)/2.
%K nonn
%O 2,2
%A _R. H. Hardin_ Mar 02 2009
|
