OFFSET
1,1
COMMENTS
Column 2 of A189814.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..200
FORMULA
Empirical: a(n) = 6*n^2 + 26*n - 42 for n>3.
Conjectures from Colin Barker, May 03 2018: (Start)
G.f.: 2*x*(7 + x + 2*x^2 - 3*x^3 + x^4 - 2*x^5) / (1 - x)^3.
a(n) = 3*a(n-1) - 3*a(n-2) + a(n-3) for n>6.
(End)
EXAMPLE
Some solutions for n=3:
..3..0....0..1....2..1....1..1....2..0....3..0....1..1....2..2....0..0....3..1
..0..0....0..0....1..0....0..1....2..1....2..0....0..2....1..1....0..2....1..1
..3..1....3..1....3..0....1..2....3..0....3..2....2..2....3..1....3..0....3..2
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Apr 28 2011
STATUS
approved