OFFSET
1,1
COMMENTS
Column 2 of A242322.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = a(n-1) + 2*a(n-2) + 2*a(n-3) + 2*a(n-4) - a(n-5) - a(n-6).
Empirical g.f.: x*(25 + 36*x + 34*x^2 + 20*x^3 - 18*x^4 - 13*x^5) / ((1 + x)*(1 - 2*x - 2*x^3 + x^5)). - Colin Barker, Mar 19 2018
EXAMPLE
Some solutions for n=5:
..0....0....0....0....0....0....0....0....0....0....0....0....0....0....0....0
..1....1....1....1....1....1....1....1....1....0....1....0....0....1....1....1
..0....2....1....2....1....0....2....1....0....1....0....1....1....0....1....2
..1....2....2....0....2....1....2....2....0....2....2....1....0....2....0....0
..2....0....0....1....0....2....2....2....2....2....2....2....2....1....2....1
..1....2....2....0....2....0....0....0....1....0....1....2....2....2....1....2
..1....1....1....2....2....1....1....1....0....1....2....0....2....0....2....1
..0....1....2....2....1....1....1....0....0....2....0....1....1....2....0....2
..0....0....2....0....2....0....2....0....1....2....2....0....0....0....2....0
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, May 10 2014
STATUS
approved