OFFSET
1,1
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = 7*a(n-1) + 10*a(n-2) - 26*a(n-3) - 64*a(n-4) - 40*a(n-5) for n>6.
Empirical g.f.: x*(4 + x - 34*x^2 - 26*x^3 - 28*x^4 - 48*x^5) / (1 - 7*x - 10*x^2 + 26*x^3 + 64*x^4 + 40*x^5). - Colin Barker, Feb 20 2019
EXAMPLE
Some solutions for n=4:
..0..1..2. .0..1..2. .0..0..1. .0..1..0. .0..1..1. .0..1..2. .0..1..0
..2..1..0. .2..1..2. .2..1..2. .0..1..0. .0..2..0. .0..2..0. .0..1..0
..2..1..2. .2..0..0. .2..0..2. .0..1..2. .2..1..0. .0..2..0. .2..1..2
..0..0..1. .2..1..1. .2..0..2. .2..1..2. .2..0..2. .1..1..0. .0..0..1
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jan 25 2017
STATUS
approved