OFFSET
1,1
COMMENTS
Column 2 of A297907.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = a(n-1) + 3*a(n-2) + 8*a(n-3) - 4*a(n-4) - 16*a(n-5) for n>6.
Empirical g.f.: x*(1 + 2*x)*(2 - 2*x - 3*x^2 - 12*x^3 + 12*x^4) / (1 - x - 3*x^2 - 8*x^3 + 4*x^4 + 16*x^5). - Colin Barker, Feb 19 2018
EXAMPLE
Some solutions for n=7:
..0..1. .0..1. .0..1. .0..1. .0..0. .0..0. .0..1. .0..0. .0..1. .0..1
..1..0. .1..0. .1..0. .0..1. .0..0. .1..1. .0..1. .1..1. .0..1. .0..1
..0..0. .1..1. .0..0. .0..0. .1..0. .1..1. .0..0. .1..1. .1..1. .0..0
..1..0. .1..0. .1..0. .0..1. .0..1. .1..0. .0..0. .0..0. .1..0. .0..0
..0..1. .0..1. .0..0. .0..0. .0..0. .1..0. .0..1. .1..1. .1..1. .1..1
..0..0. .1..1. .1..0. .0..1. .0..1. .0..0. .0..0. .1..1. .0..1. .0..0
..0..0. .1..1. .1..0. .0..1. .0..1. .0..0. .0..0. .0..0. .0..1. .0..0
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jan 08 2018
STATUS
approved