OFFSET
1,2
COMMENTS
Row 4 of A187286.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..50
FORMULA
Empirical: a(n) = 380*n^2 - 1532*n + 1224 for n>5.
Conjectures from Colin Barker, Apr 22 2018: (Start)
G.f.: 4*x^2*(2 + 66*x + 104*x^2 + 43*x^3 - 15*x^4 - 5*x^5 - 5*x^6) / (1 - x)^3.
a(n) = 3*a(n-1) - 3*a(n-2) + a(n-3) for n>8.
(End)
EXAMPLE
Some solutions for 4 X 4:
..0..1..0..0....0..0..0..0....1..0..0..0....0..0..0..0....0..1..0..0
..0..2..0..0....0..0..4..0....0..0..0..0....0..0..1..0....3..2..0..0
..0..4..0..0....0..0..0..0....2..3..0..0....0..0..2..3....4..0..0..0
..0..3..0..0....0..1..3..2....0..4..0..0....0..0..0..4....0..0..0..0
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Mar 08 2011
STATUS
approved