OFFSET
1,1
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = 480*n^2 - 3394*n + 6449 for n>5.
Conjectures from Colin Barker, Dec 06 2018: (Start)
G.f.: x*(7 + 8*x + 61*x^2 + 192*x^3 + 347*x^4 + 295*x^5 + 45*x^6 + 5*x^7) / (1 - x)^3.
a(n) = 3*a(n-1) - 3*a(n-2) + a(n-3) for n>8.
(End)
EXAMPLE
Some solutions for n=4:
..0..1..1..1....0..0..1..1....0..1..1..2....0..0..1..1....0..1..1..1
..0..1..1..1....1..1..1..1....0..1..1..2....0..0..1..1....1..1..2..2
..0..1..1..2....1..2..2..2....0..1..1..2....0..1..1..2....1..2..2..2
..1..1..2..2....1..2..2..3....1..1..2..2....1..1..1..2....2..2..3..3
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Dec 22 2014
STATUS
approved