OFFSET
1,1
COMMENTS
Row 1 of A255107.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = (1/120)*n^5 + (1/6)*n^4 + (19/24)*n^3 + (11/6)*n^2 + (16/5)*n + 3.
Empirical g.f.: x*(9 - 28*x + 45*x^2 - 39*x^3 + 17*x^4 - 3*x^5) / (1 - x)^6. - Colin Barker, Jan 24 2018
EXAMPLE
Some solutions for n=4:
..1....1....0....0....0....1....0....0....1....2....0....0....1....1....0....0
..1....2....0....0....0....1....1....1....1....1....2....2....2....0....0....0
..0....0....2....2....1....2....0....1....1....2....2....2....2....0....2....2
..0....2....1....0....1....2....0....2....1....2....2....1....0....0....2....0
..1....2....1....2....2....1....1....1....2....2....0....2....2....0....1....1
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Feb 14 2015
STATUS
approved