A157600 Half the number of length n integer sequences with sum zero and sum of squares 9248.

1, 3, 102, 30030, 5399445, 596031513, 53828636911, 4407428497293, 353304900193680, 27176309595536035, 2030727740280136689, 147839184902264090742, 10306962174706523122706, 683847390057269455279395

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,0,9248)/2.

Crossrefs

Sequence in context: A157549 A157566 A364418 * A139908 A128070 A323036

Adjacent sequences: A157597 A157598 A157599 * A157601 A157602 A157603

Keyword

nonn

Author

R. H. Hardin Mar 02 2009

Status

approved