OFFSET
1,2
COMMENTS
Column 3 of A231246.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = 4*a(n-1) +16*a(n-2) +26*a(n-3) +37*a(n-4) +6*a(n-5).
Empirical g.f.: 2*x^2*(7 + 11*x + 8*x^2) / (1 - 4*x - 16*x^2 - 26*x^3 - 37*x^4 - 6*x^5). - Colin Barker, Feb 09 2018
EXAMPLE
Some solutions for n=4:
..0..1..0....0..3..2....0..3..0....0..1..0....0..3..2....0..1..2....0..1..0
..2..3..2....2..1..0....2..1..0....0..3..2....0..1..0....2..3..0....0..3..2
..0..3..0....2..3..2....2..3..2....0..3..2....0..3..0....0..3..2....2..1..0
..2..1..2....2..1..0....2..1..2....2..1..2....0..1..2....0..1..2....2..3..0
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Nov 06 2013
STATUS
approved