OFFSET
1,1
COMMENTS
Column 2 of A267952.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = 10*a(n-1) - 8*a(n-2) - 163*a(n-3) + 306*a(n-4) + 684*a(n-5) - 1296*a(n-6).
Empirical g.f.: 3*x*(1 - x - 18*x^2 + 36*x^3 + 72*x^4 - 144*x^5) / ((1 + 3*x)*(1 - 4*x)*(1 - 7*x + 9*x^2)*(1 - 2*x - 12*x^2)). - Colin Barker, Mar 21 2018
EXAMPLE
Some solutions for n=6:
..0..1....0..1....0..0....0..2....0..2....0..1....0..1....0..1....0..2....0..2
..2..2....1..2....2..1....1..1....0..0....0..0....2..0....2..1....1..0....2..2
..1..0....2..0....2..0....1..1....1..1....1..1....0..0....1..2....0..2....1..1
..2..2....2..0....1..2....0..2....0..2....2..2....1..2....2..1....0..1....1..2
..1..2....1..1....0..1....1..2....2..0....1..1....0..0....2..2....1..0....0..1
..0..1....0..1....0..0....2..1....0..1....1..0....2..1....1..2....1..1....1..2
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jan 22 2016
STATUS
approved