OFFSET
1,2
COMMENTS
Column 2 of A221192.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..20
FORMULA
Empirical: a(n) = 15*a(n-1) - 41*a(n-2) - 42*a(n-3) + 174*a(n-4) - 86*a(n-5) - 2*a(n-6).
Empirical g.f.: x*(1 + 16*x - 106*x^2 + 148*x^3 - 58*x^4) / (1 - 15*x + 41*x^2 + 42*x^3 - 174*x^4 + 86*x^5 + 2*x^6). - Colin Barker, Mar 14 2018
EXAMPLE
Some solutions for n=3:
..0..0....0..2....1..1....2..2....0..0....1..0....0..0....0..2....0..1....2..0
..1..3....0..1....0..1....0..1....1..1....1..2....2..0....2..1....4..0....2..0
..1..1....2..1....3..0....0..1....2..2....1..1....1..3....1..0....0..1....0..2
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jan 04 2013
STATUS
approved