OFFSET
1,1
COMMENTS
Column 2 of A220217.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = 2*a(n-1) + 2*a(n-2) + 3*a(n-3) + 7*a(n-4) + 9*a(n-5) + 12*a(n-6) + 11*a(n-7) + 4*a(n-8) + 4*a(n-9).
Empirical g.f.: x*(2 + 2*x + 7*x^2 + 11*x^3 + 13*x^4 + 16*x^5 + 12*x^6 + 5*x^7 + 4*x^8) / (1 - 2*x - 2*x^2 - 3*x^3 - 7*x^4 - 9*x^5 - 12*x^6 - 11*x^7 - 4*x^8 - 4*x^9). - Colin Barker, Jul 31 2018
EXAMPLE
Some solutions for n=3:
..0..1....1..0....0..0....0..0....1..1....1..1....0..0....1..1....1..0....0..1
..1..1....0..0....0..0....1..0....1..0....1..0....0..0....0..1....1..1....1..1
..1..1....0..0....0..0....1..1....0..0....1..1....0..1....0..0....0..1....0..1
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Dec 07 2012
STATUS
approved