OFFSET
1,2
COMMENTS
Row 4 of A187377
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..50
FORMULA
Empirical: a(n) = 27*n^2 - 97*n + 88 for n>2.
Empirical G.f.: 2*x^2*(2+14*x+12*x^2-x^3)/(1-x)^3. [Colin Barker, Jan 22 2012]
EXAMPLE
Some solutions for 4X4
..0..0..0..0....0..0..0..0....0..0..0..0....0..0..0..2....4..0..0..0
..3..0..0..0....0..0..2..0....0..0..0..0....0..0..1..3....0..3..0..0
..4..2..0..0....0..0..3..1....3..1..0..0....0..0..0..4....0..0..2..0
..0..0..1..0....0..0..4..0....4..2..0..0....0..0..0..0....0..0..0..1
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin Mar 09 2011
STATUS
approved