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A157584
Half the number of length n integer sequences with sum zero and sum of squares 5408.
1
1, 9, 90, 17270, 2392575, 203322273, 14072688875, 881578169937, 54028224275760, 3177868465756435, 181594395820598805, 10109617693345774539, 538976083520642296074, 27345902242485061861185, 1326768997661185039512750
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,0,5408)/2.
CROSSREFS
Sequence in context: A157545 A274953 A157558 * A077334 A020243 A239867
KEYWORD
nonn
AUTHOR
R. H. Hardin Mar 02 2009
STATUS
approved