OFFSET
1,1
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = (1/120)*n^5 + (1/24)*n^4 + (5/24)*n^3 + (35/24)*n^2 + (77/60)*n + 1.
Conjectures from Colin Barker, Sep 07 2018: (Start)
G.f.: x*(2 - x)*(2 - 5*x + 6*x^2 - 3*x^3 + x^4) / (1 - x)^6.
a(n) = 6*a(n-1) - 15*a(n-2) + 20*a(n-3) - 15*a(n-4) + 6*a(n-5) - a(n-6) for n>6.
(End)
EXAMPLE
Some solutions for n=4:
..0..0....1..1....1..0....1..1....0..0....0..0....1..0....0..0....1..0....1..0
..0..0....1..0....0..1....1..0....0..0....0..0....1..0....0..1....0..0....0..0
..0..1....0..0....0..0....0..0....0..0....0..1....0..0....0..1....0..0....0..1
..1..1....0..1....0..1....0..0....0..1....0..1....0..0....0..0....0..0....0..0
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jun 30 2013
STATUS
approved