OFFSET
1,2
COMMENTS
Column 2 of A297858.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = 3*a(n-1) - 2*a(n-2) + 4*a(n-3) - 10*a(n-4) + 4*a(n-5) for n>6.
Empirical g.f.: x*(1 - 6*x^3 - 4*x^4 + 4*x^5) / ((1 - 2*x)*(1 - x - 4*x^3 + 2*x^4)). - Colin Barker, Feb 19 2018
EXAMPLE
Some solutions for n=7:
..0..1. .0..1. .0..1. .0..0. .0..1. .0..1. .0..0. .0..0. .0..1. .0..0
..0..1. .1..0. .0..1. .1..0. .0..1. .0..1. .1..1. .1..1. .0..1. .0..1
..0..1. .1..0. .1..0. .1..1. .0..1. .0..1. .0..1. .1..0. .1..0. .1..1
..1..0. .0..1. .0..1. .1..1. .1..0. .0..1. .0..0. .0..0. .1..0. .0..0
..1..0. .0..1. .0..1. .1..0. .1..0. .1..0. .0..0. .0..0. .1..0. .1..1
..0..1. .0..1. .0..1. .0..0. .0..1. .1..0. .1..0. .0..1. .0..1. .0..1
..1..0. .1..0. .0..1. .1..1. .0..1. .1..0. .1..1. .1..1. .0..1. .0..0
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jan 07 2018
STATUS
approved