OFFSET
1,1
COMMENTS
Column 2 of A281837.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = 3*a(n-1) +3*a(n-2) +2*a(n-3)
EXAMPLE
Some solutions for n=4
..0..0. .0..0. .0..1. .0..0. .0..0. .0..0. .0..0. .0..1. .0..0. .0..1
..0..1. .0..0. .1..0. .1..0. .1..0. .1..1. .1..1. .1..0. .1..0. .0..1
..0..0. .0..1. .1..1. .0..1. .1..1. .0..1. .0..1. .1..0. .0..1. .1..1
..0..0. .0..0. .1..0. .0..0. .0..0. .0..0. .0..1. .1..1. .0..1. .1..1
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jan 31 2017
STATUS
approved