OFFSET
1,1
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = 491*a(n-1) - 22099*a(n-2) + 21609*a(n-3).
Conjectures from Colin Barker, Oct 10 2018: (Start)
G.f.: x*(23 - 4071*x + 17248*x^2) / ((1 - x)*(1 - 49*x)*(1 - 441*x)).
a(n) = (2205 + 486*49^n + 125*441^n) / 3528.
(End)
EXAMPLE
Some solutions for n=2:
..0..1..2..1....0..1..1..1....0..1..5..1....0..0..1..2....0..1..2..1
..0..2..1..1....1..5..5..2....2..4..3..1....3..3..0..3....2..1..2..0
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Dec 06 2013
STATUS
approved