OFFSET
1,1
COMMENTS
Column 5 of A184548.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..200
FORMULA
Empirical: a(n) = (1/5040)*n^7 + (1/120)*n^6 + (53/360)*n^5 + (17/12)*n^4 + (5767/720)*n^3 + (3063/40)*n^2 + (11959/70)*n + 52.
Conjectures from Colin Barker, Apr 13 2018: (Start)
G.f.: x*(309 - 1680*x + 3943*x^2 - 5120*x^3 + 3955*x^4 - 1819*x^5 + 465*x^6 - 52*x^7) / (1 - x)^8.
a(n) = 8*a(n-1) - 28*a(n-2) + 56*a(n-3) - 70*a(n-4) + 56*a(n-5) - 28*a(n-6) + 8*a(n-7) - a(n-8) for n>8.
(End)
EXAMPLE
Some solutions for 4 X 7:
..0..0..0..0..0..0..0....0..0..0..0..0..0..0....0..0..1..1..1..1..1
..0..0..0..0..0..0..1....0..0..0..0..0..1..1....1..1..1..1..1..1..1
..0..0..0..0..0..1..1....0..0..1..1..1..0..0....1..1..1..1..1..1..1
..0..0..0..1..1..1..0....1..1..1..1..1..1..1....1..1..1..1..1..1..1
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jan 16 2011
STATUS
approved