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A157601 Half the number of length n integer sequences with sum zero and sum of squares 9522. 1

%I

%S 1,3,450,35490,3461325,429808743,45598808332,4382814679428,

%T 396120762708465,32858020705796385,2495992345644237990,

%U 177151945927883401410,12079996873394323662971,800952129262668313107765

%N Half the number of length n integer sequences with sum zero and sum of squares 9522.

%H R. H. Hardin, <a href="/A157601/b157601.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,0,9522)/2.

%K nonn

%O 2,2

%A _R. H. Hardin_ Mar 02 2009

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Last modified May 25 01:56 EDT 2022. Contains 354047 sequences. (Running on oeis4.)