OFFSET
1,2
COMMENTS
Row 4 of A187189
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..28
FORMULA
Empirical: a(n) = 8*n^5 - 34*n^4 + 48*n^3 - 22*n^2.
Empirical G.f.: 8*x^2*(1+30*x+75*x^2+14*x^3)/(1-x)^6. [Colin Barker, Jan 22 2012]
EXAMPLE
Some solutions for 3X3
..0..4..0....2..1..0....0..1..2....1..0..0....0..0..4....4..2..3....3..2..0
..2..3..1....3..0..0....4..0..3....2..3..4....0..1..2....0..0..0....0..0..0
..0..0..0....4..0..0....0..0..0....0..0..0....0..0..3....0..1..0....4..1..0
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin Mar 06 2011
STATUS
approved