OFFSET
1,3
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = 14*a(n-1) - 57*a(n-2) + 88*a(n-3) - 256*a(n-4) + 240*a(n-5) - 320*a(n-6) + 256*a(n-7) - 64*a(n-8).
Empirical g.f.: 2*x^3*(3 - 2*x + 4*x^2)*(5 + 2*x - 12*x^2) / (1 - 7*x + 4*x^2 - 16*x^3 + 8*x^4)^2. - Colin Barker, Feb 20 2019
EXAMPLE
Some solutions for n=4:
..0..0. .0..1. .0..1. .0..1. .0..0. .0..0. .0..1. .0..0. .0..1. .0..0
..0..1. .0..1. .0..1. .1..1. .1..2. .1..2. .0..2. .1..0. .0..2. .1..0
..2..0. .2..1. .0..2. .1..0. .2..2. .2..2. .0..0. .2..1. .1..1. .0..0
..1..2. .0..1. .0..1. .2..1. .2..0. .0..0. .0..2. .1..1. .2..2. .2..0
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Feb 06 2017
STATUS
approved