OFFSET
1,1
COMMENTS
Column 2 of A206215.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = a(n-1) + 6*a(n-2) + 4*a(n-3) - 10*a(n-4) for n>6.
Empirical g.f.: x*(45 + 85*x - 64*x^2 - 304*x^3 - 82*x^4 + 80*x^5) / ((1 - x)*(1 - 6*x^2 - 10*x^3)). - Colin Barker, Jun 14 2018
EXAMPLE
Some solutions for n=4:
..0..0..0....0..1..2....0..1..1....0..1..0....0..0..1....0..1..1....0..1..2
..1..2..1....0..0..1....0..2..0....2..0..0....0..2..0....1..2..1....0..0..1
..1..0..1....1..0..0....0..1..0....0..0..1....2..0..0....1..1..2....1..0..0
..1..2..1....0..2..0....0..2..0....0..1..2....0..0..2....2..1..1....2..1..1
..0..0..0....0..0..1....0..1..0....1..2..2....0..2..1....1..2..2....1..1..2
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Feb 04 2012
STATUS
approved