OFFSET
1,1
COMMENTS
Column 1 of A231343.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = 3*a(n-1) + a(n-2) - 7*a(n-3) + a(n-4) + 3*a(n-5).
Empirical g.f.: x*(3 - 5*x - 8*x^2 + 8*x^3 + 6*x^4) / ((1 - x)*(1 - x - x^2)*(1 - x - 3*x^2)). - Colin Barker, Feb 24 2018
EXAMPLE
Some solutions for n=5:
..0..1....0..0....0..0....0..0....0..0....0..0....0..0....0..0....0..0....0..0
..0..1....0..0....1..1....0..0....0..0....1..1....1..1....0..0....0..0....0..0
..0..1....1..1....1..1....1..1....1..1....1..1....1..1....0..0....0..0....1..1
..0..1....1..1....2..2....1..1....1..1....0..0....2..2....0..0....0..0....1..1
..0..1....1..1....2..2....1..1....0..0....0..0....2..2....0..0....1..1....2..2
..0..1....1..1....3..3....2..2....0..0....1..1....0..0....1..1....1..1....2..2
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Nov 07 2013
STATUS
approved