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A157578
Half the number of length n integer sequences with sum zero and sum of squares 4232.
1
1, 3, 150, 15210, 1639575, 123643611, 7614820759, 421492526271, 22902703731540, 1192049263269315, 60248523072916695, 2966823784716819963, 139916416171825355244, 6279781745619795030660, 269526833541639073889370
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,0,4232)/2.
CROSSREFS
Sequence in context: A118840 A111816 A157555 * A137802 A100203 A287319
KEYWORD
nonn
AUTHOR
R. H. Hardin Mar 02 2009
STATUS
approved