OFFSET
1,1
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = 2*a(n-1) + a(n-2) - a(n-4) - a(n-5).
Empirical g.f.: x*(19 + 7*x - 6*x^2 - 12*x^3 - 9*x^4) / ((1 - x)*(1 - x - 2*x^2 - 2*x^3 - x^4)). - Colin Barker, Nov 03 2018
EXAMPLE
Some solutions for n=10:
..1....2....1....2....0....1....0....1....0....0....2....0....0....2....0....0
..1....1....1....2....0....1....2....1....2....1....2....1....0....1....1....1
..1....1....1....0....2....1....1....1....0....1....0....2....2....0....1....1
..1....0....0....2....1....1....1....1....2....2....2....0....0....2....2....0
..1....2....2....0....1....1....1....2....2....0....1....2....2....2....0....1
..0....2....0....1....2....2....0....1....0....1....1....0....1....0....2....2
..2....0....1....1....0....1....2....0....2....1....0....2....1....2....2....0
..2....1....1....1....2....0....0....2....2....1....1....1....1....2....0....1
..0....2....2....1....0....1....0....1....0....1....1....1....0....0....0....1
..2....1....1....0....1....2....2....1....1....1....1....0....1....0....2....0
..2....0....0....1....1....1....0....2....2....2....1....2....1....2....2....1
..0....1....1....1....1....0....2....1....0....1....1....0....2....0....0....2
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Aug 04 2014
STATUS
approved