OFFSET
1,1
COMMENTS
Column 1 of A206343.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = a(n-1) + 3*a(n-2) - 3*a(n-3) for n>10.
Conjectures from Colin Barker, Jun 15 2018: (Start)
G.f.: x*(192 - 96*x - 217*x^2 + 129*x^3 + 3*x^4 - 19*x^5 - 9*x^6 - x^7 + 4*x^8 + 2*x^9) / ((1 - x)*(1 - 3*x^2)).
a(n) = 872 * 3^((n-9)/2+3/2) + 6 for n>7 and even.
a(n) = 12313 * 3^((n-9)/2) + 6 for n>7 and odd.
(End)
EXAMPLE
Some solutions for n=4:
..1..1....2..1....1..3....0..3....3..0....3..0....0..1....0..1....1..0....1..1
..3..0....3..0....2..0....3..0....0..3....0..3....2..0....1..0....0..1....1..0
..0..3....0..3....0..2....0..3....2..0....3..0....0..2....0..1....2..0....0..1
..1..0....3..0....1..0....2..0....0..2....0..3....2..0....1..0....0..2....3..0
..0..1....0..3....0..1....0..2....1..0....1..1....0..2....0..1....3..1....0..3
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Feb 06 2012
STATUS
approved