OFFSET
1,1
COMMENTS
Column 4 of A208007.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = 6*a(n-1) - 3*a(n-2) - 36*a(n-3) + 54*a(n-4) + 24*a(n-5) - 69*a(n-6) + 12*a(n-7) + 19*a(n-8) - 6*a(n-9) for n>10.
G.f.: x*(9 + 27*x - 238*x^2 - 223*x^3 + 1588*x^4 - 299*x^5 - 2044*x^6 + 767*x^7 + 603*x^8 - 234*x^9) / ((1 - x)*(1 + x)*(1 - 3*x + x^2)*(1 - x - x^2)*(1 - 2*x - 7*x^2 + 6*x^3)). - Colin Barker, Jun 26 2018
EXAMPLE
Some solutions for n=4:
..1..0..1..1....0..1..0..1....1..1..1..0....1..1..1..0....1..1..0..1
..0..1..1..0....0..0..0..0....0..0..0..0....1..0..1..1....0..1..0..1
..1..0..1..1....0..1..0..1....1..1..1..0....1..1..1..0....0..1..1..1
..0..1..1..0....0..0..0..0....0..0..0..0....1..0..1..1....0..1..0..1
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Feb 22 2012
STATUS
approved