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A157570 Half the number of length n integer sequences with sum zero and sum of squares 2888. 1

%I

%S 1,9,114,11430,928665,57312801,2929653363,133959064275,6012597282660,

%T 258520740868390,10793900036914731,439085564014381089,

%U 17106142080255638592,634240156516816014270,22487281301691416873070

%N Half the number of length n integer sequences with sum zero and sum of squares 2888.

%H R. H. Hardin, <a href="/A157570/b157570.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,0,2888)/2.

%K nonn

%O 2,2

%A _R. H. Hardin_ Mar 02 2009

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Last modified October 30 06:31 EDT 2020. Contains 338077 sequences. (Running on oeis4.)