OFFSET
1,1
COMMENTS
Column 4 of A255107.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = 3*a(n-1) -3*a(n-2) +a(n-3) +12*a(n-4) -18*a(n-5) +7*a(n-6) -3*a(n-8) +a(n-9).
Empirical g.f.: x*(147 - 110*x + 237*x^2 + 384*x^3 - 1014*x^4 + 438*x^5 - 69*x^6 - 172*x^7 + 66*x^8) / (1 - 3*x + 3*x^2 - x^3 - 12*x^4 + 18*x^5 - 7*x^6 + 3*x^8 - x^9). - Colin Barker, Jan 24 2018
EXAMPLE
Some solutions for n=4:
..1....2....1....0....2....0....1....1....1....0....1....0....0....1....0....0
..1....0....0....0....0....0....2....2....1....1....1....0....0....2....2....1
..2....1....0....1....0....1....0....1....0....1....0....1....0....1....2....0
..0....1....0....0....0....0....1....2....0....0....0....1....0....1....2....0
..0....1....1....1....0....1....1....2....2....1....2....0....2....1....0....1
..0....1....2....1....2....2....1....2....2....1....2....1....2....2....0....2
..1....0....2....2....2....2....1....0....2....1....2....1....2....2....0....1
..1....0....0....1....0....1....2....0....0....0....1....2....2....2....0....2
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Feb 14 2015
STATUS
approved