OFFSET
1,1
COMMENTS
Column 3 of A221590.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..174
FORMULA
Empirical: a(n) = 12*a(n-1) -32*a(n-2) for n>6.
Conjectures from Colin Barker, Aug 09 2018: (Start)
G.f.: 2*x*(2 - 4*x + 33*x^2 + 12*x^3 - 164*x^4 + 32*x^5) / ((1 - 4*x)*(1 - 8*x)).
a(n) = 8^n - 169*2^(2*n-7) for n>4.
(End)
EXAMPLE
Some solutions for n=3:
..0..1..0....0..1..0....1..0..1....1..1..1....0..1..0....0..1..0....1..1..1
..0..1..0....0..0..1....1..0..0....0..1..0....1..0..0....0..0..0....1..1..1
..0..1..1....1..1..1....0..1..0....0..0..1....0..1..1....1..1..1....0..1..1
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jan 20 2013
STATUS
approved