OFFSET
1,1
COMMENTS
Row 2 of A223556.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = 7*a(n-1) - 4*a(n-2) for n>3.
Empirical g.f.: 3*x*(2 - x)*(1 - 2*x) / (1 - 7*x + 4*x^2). - Colin Barker, Aug 21 2018
EXAMPLE
Some solutions for n=3:
..0..1..0....0..3..4....0..1..0....0..1..0....0..1..0....0..2..1....0..3..0
..0..2..5....4..5..2....0..3..0....0..2..1....0..1..0....1..2..1....4..1..4
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Mar 22 2013
STATUS
approved