A157596 Half the number of length n integer sequences with sum zero and sum of squares 8192.

1, 3, 6, 27310, 4493895, 469762041, 39763084319, 3062924462367, 231122336887800, 16732612596774745, 1176767971442596731, 80630592887297229153, 5290690279278336041746, 330378602282944731759075

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,0,8192)/2.

Crossrefs

Sequence in context: A157564 A122182 A276701 * A111316 A297530 A222010

Adjacent sequences: A157593 A157594 A157595 * A157597 A157598 A157599

Keyword

nonn

Author

R. H. Hardin Mar 02 2009

Status

approved