OFFSET
1,1
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = 6400*n^2 - 59190*n + 143483 for n>7.
Conjectures from Colin Barker, Dec 06 2018: (Start)
G.f.: x*(11 + 20*x + 162*x^2 + 758*x^3 + 2457*x^4 + 4458*x^5 + 3884*x^6 + 865*x^7+ 170*x^8 + 15*x^9) / (1 - x)^3.
a(n) = 3*a(n-1) - 3*a(n-2) + a(n-3) for n>10.
(End)
EXAMPLE
Some solutions for n=4:
..0..1..1..2..2....0..1..1..2..3....0..0..1..2..3....0..1..1..2..2
..0..1..1..2..3....1..1..1..2..3....1..1..1..2..3....1..1..1..2..3
..1..1..2..2..3....2..2..2..2..3....1..2..2..2..3....1..1..2..2..3
..1..2..2..2..3....2..3..3..3..3....1..2..2..3..3....2..2..2..3..3
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Dec 22 2014
STATUS
approved