OFFSET
1,1
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = 6*a(n-1) + a(n-2) - 6*a(n-3) for n>4.
Conjectures from Colin Barker, Oct 07 2018: (Start)
G.f.: x*(3 - 7*x - 4*x^2 + 3*x^3) / ((1 - x)*(1 + x)*(1 - 6*x)).
a(n) = (24 + 25*6^n) / 84 for n even.
a(n) = (60 + 25*6^n) / 84 for n>1 and odd.
(End)
EXAMPLE
Some solutions for n=5:
..0..1..0..1..3....0..1..3..2..0....0..0..0..0..1....0..1..1..1..0
..0..0..1..1..3....0..2..0..1..0....1..0..1..0..1....0..0..1..0..1
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Dec 04 2013
STATUS
approved