OFFSET
1,1
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..48
FORMULA
Empirical: a(n) = 16*a(n-4) for n>5.
Empirical g.f.: x*(81 + 800*x + 2000*x^2 + 3744*x^3 + 6704*x^4) / ((1 - 2*x)*(1 + 2*x)*(1 + 4*x^2)). - Colin Barker, Dec 13 2018
EXAMPLE
Some solutions for n=4:
..0..0..1..0..2....0..2..1..1..2....1..2..0..2..1....2..0..2..0..2
..1..1..0..1..0....0..0..1..0..2....2..1..1..0..1....0..2..1..1..0
..1..1..2..1..2....1..1..0..1..0....1..2..0..1..1....1..1..2..0..1
..1..2..1..2..0....1..1..2..1..2....2..1..1..0..2....0..2..1..1..0
..1..0..2..2..2....1..2..1..2..1....2..2..1..0..0....2..2..1..1..1
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jan 01 2015
STATUS
approved