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A157569 Half the number of length n integer sequences with sum zero and sum of squares 2738. 1
1, 9, 234, 13330, 759255, 39386151, 1941592492, 100065421116, 4986199986795, 221853806154915, 9037873481632974, 346801773380423010, 12750860059402207015, 453349862010556020825, 15650738757439717731720 (list; graph; refs; listen; history; text; internal format)
OFFSET

2,2

LINKS

R. H. Hardin, Table of n, a(n) for n=2..50

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,0,2738)/2.

CROSSREFS

Sequence in context: A276536 A288683 A302914 * A279492 A297747 A211052

Adjacent sequences:  A157566 A157567 A157568 * A157570 A157571 A157572

KEYWORD

nonn

AUTHOR

R. H. Hardin Mar 02 2009

STATUS

approved

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Last modified October 22 19:03 EDT 2020. Contains 337953 sequences. (Running on oeis4.)