A157555 Half the number of length n integer sequences with sum zero and sum of squares 1058.

1, 3, 150, 5070, 182175, 5887791, 180232444, 5773910724, 178835952285, 4946264437455, 125256800641170, 2987737855296558, 68285219070825029, 1509200139206357640, 32387266774022554680, 675011623200542959496

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,0,1058)/2.

Crossrefs

Sequence in context: A181748 A118840 A111816 * A157578 A137802 A100203

Adjacent sequences: A157552 A157553 A157554 * A157556 A157557 A157558

Keyword

nonn

Author

R. H. Hardin Mar 02 2009

Status

approved