OFFSET
1,1
COMMENTS
Column 4 of A224374.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = 15*a(n-1) - 58*a(n-2) + 105*a(n-3) + 20*a(n-4) - 183*a(n-5) + 220*a(n-6) + 240*a(n-7) for n>8.
Empirical g.f.: x*(46 + 8*x - 194*x^2 - 673*x^3 + 468*x^4 + 724*x^5 - 90*x^6 - 45*x^7) / (1 - 15*x + 58*x^2 - 105*x^3 - 20*x^4 + 183*x^5 - 220*x^6 - 240*x^7). - Colin Barker, Aug 30 2018
EXAMPLE
Some solutions for n=3:
..0..1..2..2....1..0..0..0....1..1..1..1....0..1..1..0....0..0..1..2
..2..2..2..2....2..0..0..0....2..1..1..0....1..1..1..0....0..1..2..2
..2..2..2..1....2..2..0..0....1..1..2..1....2..2..2..1....1..2..2..0
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Apr 05 2013
STATUS
approved