OFFSET
1,2
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = 5*a(n-1) + 8*a(n-2).
Conjectures from Colin Barker, Feb 07 2019: (Start)
G.f.: 6*x^2 / (1 - 5*x - 8*x^2).
a(n) = 2^(-3-n) * ((57-5*sqrt(57))*(5+sqrt(57))^n + (5-sqrt(57))^n*(57+5*sqrt(57))) / 19.
(End)
EXAMPLE
Some solutions for n=4:
..0..1. .0..2. .0..1. .0..1. .0..1. .0..1. .0..1. .0..2. .0..2. .0..2
..0..2. .1..2. .0..2. .0..2. .0..2. .2..2. .1..2. .1..1. .1..1. .1..0
..2..1. .2..0. .2..0. .1..2. .1..2. .1..1. .0..1. .0..1. .0..2. .2..1
..2..0. .2..1. .1..1. .0..0. .1..1. .0..2. .0..0. .2..2. .1..1. .0..1
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Nov 08 2016
STATUS
approved