OFFSET
1,1
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = 12*a(n-1) + 7*a(n-2) - 40*a(n-3) + 12*a(n-4).
Empirical g.f.: x*(16 - 45*x + 5*x^2 + 10*x^3) / (1 - 12*x - 7*x^2 + 40*x^3 - 12*x^4). - Colin Barker, Oct 06 2018
EXAMPLE
Some solutions for n=4:
..0..0..1..1....0..0..0..0....0..1..0..0....0..1..1..1....0..1..1..1
..0..1..1..0....1..1..1..1....0..1..1..0....3..1..1..3....0..0..0..1
..0..0..0..1....1..0..1..0....0..0..1..1....3..1..3..1....1..1..1..0
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Dec 02 2013
STATUS
approved