OFFSET
1,1
COMMENTS
Column 2 of A204076.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = 10*a(n-1) - 11*a(n-2) + 2*a(n-3).
Conjectures from Colin Barker, Jun 06 2018: (Start)
G.f.: x*(38 - 51*x + 10*x^2) / ((1 - x)*(1 - 9*x + 2*x^2)).
a(n) = 1/2 + (2^(-2-n)*(3*(9+sqrt(73))^n*(23+3*sqrt(73)) + (9-sqrt(73))^n*(-69+9*sqrt(73)))) / sqrt(73).
(End)
EXAMPLE
Some solutions for n=4:
..0..1..0....0..0..0....0..0..0....0..1..2....0..0..0....0..0..1....0..0..1
..0..0..1....0..1..0....0..1..0....1..1..1....1..0..1....1..0..0....2..0..0
..1..0..0....2..0..1....0..0..2....1..1..1....2..1..2....1..1..0....1..2..0
..1..1..0....2..2..0....1..0..0....0..1..2....0..2..2....2..1..1....1..1..2
..2..1..1....0..2..2....2..1..0....2..0..1....2..0..2....0..2..1....2..1..1
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jan 10 2012
STATUS
approved