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A157548 Half the number of length n integer sequences with sum zero and sum of squares 512. 1
1, 3, 6, 1710, 70215, 1835001, 38831135, 747772191, 14106580920, 255318883105, 4489013718651, 76895304533697, 1261399140060514, 19692099463166235, 293975822555447490, 4228706577830551202, 58957940194082852859 (list; graph; refs; listen; history; text; internal format)
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,0,512)/2.
CROSSREFS
Sequence in context: A034879 A113588 A071106 * A134901 A157564 A122182
KEYWORD
nonn
AUTHOR
R. H. Hardin Mar 02 2009
STATUS
approved

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Last modified May 22 04:07 EDT 2024. Contains 372742 sequences. (Running on oeis4.)