OFFSET
1,1
COMMENTS
Column 3 of A207488.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = 7*a(n-1) - 13*a(n-2) - 10*a(n-3) + 48*a(n-4) - 16*a(n-5) - 47*a(n-6) + 25*a(n-7) + 13*a(n-8) - 6*a(n-9) for n>10.
Empirical g.f.: x*(6 - 6*x - 92*x^2 + 131*x^3 + 307*x^4 - 425*x^5 - 365*x^6 + 401*x^7 + 131*x^8 - 82*x^9) / ((1 - x)*(1 + x)*(1 - 2*x)*(1 - 3*x + x^2)*(1 - x - x^2)*(1 - x - 3*x^2)). - Colin Barker, Mar 05 2018
EXAMPLE
Some solutions for n=4:
..1..1..0....1..0..1....0..0..1....0..1..0....0..0..1....1..1..1....1..0..0
..1..0..1....0..0..1....0..0..1....1..0..1....0..1..0....1..1..0....1..0..1
..1..0..0....0..0..1....0..0..1....0..1..0....0..0..1....1..1..1....1..0..0
..1..1..1....0..0..1....1..1..1....1..0..0....0..1..0....1..1..0....1..0..1
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Feb 18 2012
STATUS
approved