OFFSET
1,1
COMMENTS
Column 3 of A190041.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..200
FORMULA
Empirical: a(n) = 4*n - 2 for n>2.
Conjectures from Colin Barker, May 03 2018: (Start)
G.f.: x*(5 - 3*x + x^2 + x^3) / (1 - x)^2.
a(n) = 2*a(n-1) - a(n-2) for n>4.
(End)
EXAMPLE
All solutions for n=4:
..1....1....0....3....2....0....1....0....1....1....0....1....1....1
..1....1....3....3....3....1....1....1....2....1....1....2....3....1
..2....1....3....3....3....1....2....1....3....1....1....2....3....1
..2....1....3....3....3....2....3....2....3....2....1....3....3....2
..3....2....3....3....3....2....3....3....3....3....2....3....3....2
..3....3....3....3....3....3....3....3....3....3....3....3....3....3
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, May 04 2011
STATUS
approved