OFFSET
1,1
COMMENTS
Column 2 of A205170.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = 62*a(n-1) -329*a(n-2) +324*a(n-3) -84*a(n-4).
Empirical g.f.: x*(159 - 1379*x + 1466*x^2 - 392*x^3) / ((1 - 5*x + 2*x^2)*(1 - 57*x + 42*x^2)). - Colin Barker, Jun 11 2018
EXAMPLE
Some solutions for n=4:
..0..1..0....0..1..1....0..0..0....0..0..0....0..0..0....0..0..1....0..0..0
..0..1..0....0..2..1....0..1..1....0..1..0....0..1..1....0..1..1....0..1..1
..0..1..0....1..1..0....2..0..2....2..2..1....1..1..0....2..2..1....2..3..2
..0..1..1....3..2..3....2..1..0....1..3..2....0..0..2....0..3..1....3..1..1
..0..0..0....3..0..0....3..2..2....0..1..0....0..1..2....0..1..0....1..0..3
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jan 22 2012
STATUS
approved