OFFSET
1,3
FORMULA
Empirical: a(n) = 128*n^9 - 1538*n^8 + 7956*n^7 - 23556*n^6 + 44586*n^5 - 55218*n^4 + 40894*n^3 - 13252*n^2.
Empirical G.f.: 72*x^3 * (2599*x^6 +52838*x^5 +213575*x^4 +272580*x^3 +96205*x^2 +7286*x +37) / (x-1)^10. [Colin Barker, Jul 01 2012]
EXAMPLE
Some solutions for 4X4
..4..2..3..0....0..6..7..5....0..5..0..6....0..2..3..0....2..8..3..0
..5..0..0..8....0..0..0..0....8..0..0..7....7..1..6..8....1..6..5..0
..0..1..0..0....0..1..2..3....0..0..1..0....0..0..5..0....0..7..0..0
..6..0..0..7....0..0..8..4....0..4..2..3....0..0..4..0....0..0..4..0
CROSSREFS
KEYWORD
nonn,more
AUTHOR
R. H. Hardin, Mar 06 2011
STATUS
approved