A157586 Half the number of length n integer sequences with sum zero and sum of squares 5832.

1, 3, 162, 16410, 1839645, 210928977, 17676193171, 1148671947972, 71262995700540, 4352863891098140, 258238261126722129, 14806140740844716211, 815211282605034375060, 42951699550186642926270, 2166061193994862365099390

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,0,5832)/2.

Crossrefs

Sequence in context: A377253 A157440 A157559 * A341224 A042439 A364302

Adjacent sequences: A157583 A157584 A157585 * A157587 A157588 A157589

Keyword

nonn

Author

R. H. Hardin Mar 02 2009

Status

approved