OFFSET
1,1
COMMENTS
Column 7 of A208637.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = 8*a(n-1) - 21*a(n-2) + 20*a(n-3) - 5*a(n-4).
Empirical g.f.: x*(64 - 321*x + 444*x^2 - 144*x^3) / ((1 - 3*x + x^2)*(1 - 5*x + 5*x^2)). - Colin Barker, Jul 05 2018
EXAMPLE
Some solutions for n=4:
..0..1..0..0..0..0..1....0..1..1..0..0..1..0....0..0..1..0..1..1..0
..1..0..1..1..1..0..0....0..0..1..1..0..1..1....1..0..1..0..0..1..0
..0..1..0..0..1..1..1....1..0..0..1..0..0..1....0..1..0..1..0..1..0
..1..0..1..0..0..0..0....0..1..0..1..1..0..0....1..0..1..0..1..0..1
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Feb 29 2012
STATUS
approved