OFFSET
1,1
COMMENTS
Column 5 of A200251.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..136
FORMULA
Empirical: a(n) = 3*a(n-1) +2*a(n-2).
Conjectures from Colin Barker, May 20 2018: (Start)
G.f.: 3*x*(2 + x) / (1 - 3*x - 2*x^2).
a(n) = (3*2^(-2-n)*((3-sqrt(17))^n*(-5+sqrt(17)) + (3+sqrt(17))^n*(5+sqrt(17)))) / sqrt(17).
(End)
EXAMPLE
Some solutions for n=6:
..2....2....3....2....0....0....3....3....2....3....3....3....1....0....1....3
..5....4....5....5....1....3....3....4....5....4....4....4....1....0....1....3
..2....3....5....1....5....5....2....5....4....5....2....3....2....5....2....0
..5....3....1....2....2....4....4....5....5....1....5....5....4....5....5....2
..5....2....5....5....3....4....5....5....4....3....5....4....2....5....4....4
..3....4....5....4....5....5....5....5....5....4....2....4....4....3....5....5
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Nov 15 2011
STATUS
approved