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A157589
Half the number of length n integer sequences with sum zero and sum of squares 6498.
1
1, 9, 342, 26670, 1960515, 199230213, 17543249724, 1392949344564, 103992753869385, 7125947800456375, 447172658110001142, 26218227869348323614, 1476897053364550626991, 80893894777513364496600
OFFSET
2,2
LINKS
FORMULA
[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,0,6498)/2.
CROSSREFS
Sequence in context: A354689 A098652 A110695 * A055601 A225328 A203745
KEYWORD
nonn
AUTHOR
R. H. Hardin, Mar 02 2009
STATUS
approved