OFFSET
1,5
COMMENTS
Row 6 of A187606.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..50
FORMULA
Empirical: a(n) = 680*n^2 - 7188*n + 18314 for n>9.
Conjectures from Colin Barker, Apr 25 2018: (Start)
G.f.: x^5*(96 + 423*x + 238*x^2 + 546*x^3 + 243*x^4 - 312*x^5 + 403*x^6 - 277*x^7) / (1 - x)^3.
a(n) = 3*a(n-1) - 3*a(n-2) + a(n-3) for n>12.
(End)
EXAMPLE
Some solutions for 5 X 5:
..0..0..0..0..1....0..0..0..0..0....0..6..0..0..0....0..0..5..0..0
..0..0..6..0..0....0..0..6..0..0....0..0..5..0..0....4..0..0..1..0
..5..0..0..2..0....2..0..0..5..0....1..0..0..4..0....0..3..0..0..6
..0..4..0..0..0....0..1..0..0..4....0..0..0..0..3....0..0..2..0..0
..0..0..3..0..0....0..0..3..0..0....0..0..2..0..0....0..0..0..0..0
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Mar 11 2011
STATUS
approved