OFFSET
1,3
COMMENTS
Row 8 of A187586.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..50
FORMULA
Empirical: a(n) = 8819*n^2 - 63926*n + 111127 for n>6.
Conjectures from Colin Barker, Apr 24 2018: (Start)
G.f.: x^3*(34 + 2207*x + 8231*x^2 + 7443*x^3 + 1481*x^4 - 1095*x^5 - 663*x^6) / (1 - x)^3.
a(n) = 3*a(n-1) - 3*a(n-2) + a(n-3) for n>9.
(End)
EXAMPLE
Some solutions for 4 X 4:
..0..0..6..0....3..1..0..0....0..0..0..0....0..0..6..7....0..0..0..0
..4..5..7..8....4..2..7..8....1..5..6..7....4..5..0..8....1..0..0..6
..0..3..0..0....5..6..0..0....2..3..4..8....2..3..0..0....2..4..5..7
..0..1..2..0....0..0..0..0....0..0..0..0....0..1..0..0....3..0..0..8
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Mar 11 2011
STATUS
approved