A157559 - OEIS

%I #6 Oct 02 2025 22:24:30

%S 1,3,162,5470,204405,10044237,418371436,15735232164,556455670755,

%T 18061671242945,536877862194894,14910514196745102,397858116730316515,

%U 10322446421549098305,260281325962170069480,6368185576937692717552

%N Half the number of length n integer sequences with sum zero and sum of squares 1458.

%H R. H. Hardin, <a href="/A157559/b157559.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,0,1458)/2.

%K nonn

%O 2,2

%A _R. H. Hardin_, Mar 02 2009