OFFSET
1,1
COMMENTS
Column 1 of A209848.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = 11*a(n-1) - 30*a(n-2) + 4*a(n-3) + 16*a(n-4).
Empirical g.f.: x*(8 - 47*x + 16*x^2 + 32*x^3) / ((1 - x)*(1 - 4*x)*(1 - 6*x - 4*x^2)). - Colin Barker, Jul 13 2018
EXAMPLE
Some solutions for n=4:
..0..0....0..1....0..1....0..0....0..0....0..0....0..0....0..1....0..1....0..1
..0..0....0..0....0..1....1..0....0..0....0..0....1..0....0..0....0..0....0..0
..1..0....0..1....0..0....0..1....0..0....0..0....0..1....0..0....0..1....2..2
..0..0....0..1....0..0....1..0....1..0....0..0....1..0....1..0....0..0....0..0
..2..0....0..0....0..0....0..1....1..0....0..0....0..0....0..0....2..2....2..2
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Mar 14 2012
STATUS
approved