OFFSET
1,2
COMMENTS
Column 2 of A230250.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = 4*a(n-1) + a(n-2) + 4*a(n-3).
Empirical g.f.: 2*x^2*(1 - x) / (1 - 4*x - x^2 - 4*x^3). - Colin Barker, Mar 17 2018
EXAMPLE
All solutions for n=3:
..0..3....0..1....0..3....0..1....0..1....0..3
..1..2....3..2....1..0....1..2....3..2....1..2
..0..1....0..1....2..3....0..3....2..1....0..3
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Oct 13 2013
STATUS
approved