OFFSET
1,1
COMMENTS
Column 2 of A204630.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = 22*a(n-1) -14*a(n-2).
Conjectures from Colin Barker, Jun 07 2018: (Start)
G.f.: 3*x*(32 - 21*x) / (1 - 22*x + 14*x^2).
a(n) = (3*(11+sqrt(107))^n*(31+3*sqrt(107)) + (11-sqrt(107))^n*(-93+9*sqrt(107))) / (4*sqrt(107)).
(End)
EXAMPLE
Some solutions for n=3:
..0..0..0....0..0..1....0..0..1....0..1..2....0..0..1....0..0..1....0..1..0
..0..1..1....2..0..2....2..0..2....1..2..2....2..0..0....2..0..2....2..1..2
..1..2..0....0..0..2....2..2..1....0..2..1....2..0..1....1..0..2....2..1..1
..1..2..1....2..0..2....0..2..1....1..1..0....2..2..2....1..2..1....0..1..2
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jan 17 2012
STATUS
approved