OFFSET
1,1
COMMENTS
Column 2 of A222555.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..147
FORMULA
Empirical: a(n) = 5*a(n-1) - 6*a(n-2) + 2*a(n-3) - 8*a(n-4) + 12*a(n-5) - 3*a(n-6) - a(n-7).
Empirical g.f.: x*(7 - 15*x + 6*x^2 - 6*x^3 + 11*x^4 - 3*x^5 - x^6) / ((1 - x)*(1 - 4*x + 2*x^2 + 8*x^4 - 4*x^5 - x^6)). - Colin Barker, Aug 16 2018
EXAMPLE
Some solutions for n=3:
..0....0....0....0....2....0....0....1....0....1....0....1....2....2....1....1
..3....1....2....2....0....1....1....1....0....2....0....1....2....1....0....2
..2....4....1....1....2....2....3....0....3....0....1....0....0....1....1....1
..0....0....2....1....1....0....0....2....1....2....2....1....1....1....1....0
..0....0....0....1....0....2....1....1....1....0....2....2....0....0....2....1
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Feb 24 2013
STATUS
approved