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A157542 Half the number of length n integer sequences with sum zero and sum of squares 200. 1

%I

%S 1,3,42,930,17685,265041,3668483,44840097,529728300,5955342987,

%T 65311345275,699155920398,7170690213960,69964606094670,

%U 652763403442422,5868431782886486,51137730082075059,433379839761592641

%N Half the number of length n integer sequences with sum zero and sum of squares 200.

%H R. H. Hardin, <a href="/A157542/b157542.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,0,200)/2.

%K nonn

%O 2,2

%A _R. H. Hardin_ Mar 02 2009

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Last modified July 4 20:08 EDT 2022. Contains 355086 sequences. (Running on oeis4.)