OFFSET
1,1
COMMENTS
Column 3 of A221125.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..124
FORMULA
Empirical: a(n) = 26*a(n-1) - 41*a(n-2).
Conjectures from Colin Barker, Aug 03 2018: (Start)
G.f.: 8*x*(1 - x) / (1 - 26*x + 41*x^2).
a(n) = ((13-8*sqrt(2))^n*(4-7*sqrt(2)) + (4+7*sqrt(2))*(13+8*sqrt(2))^n) / 41.
(End)
EXAMPLE
Some solutions for n=3.
..2..1..0....2..1..0....1..1..1....1..1..0....1..0..1....0..1..1....1..2..0
..0..4..0....2..1..0....0..2..0....2..1..0....1..2..0....1..2..0....1..1..0
..1..0..1....2..0..1....3..0..1....3..1..0....2..1..1....1..1..2....1..3..0
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jan 02 2013
STATUS
approved