OFFSET
1,1
COMMENTS
Column 1 of A235517.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = 4*a(n-1) - 6*a(n-3) + a(n-4) + 2*a(n-5).
Conjectures from Colin Barker, Mar 19 2018: (Start)
G.f.: x*(16 - 6*x - 23*x^2 + 6*x^3 + 8*x^4) / ((1 - x)^2*(1 + x)*(1 - 3*x - 2*x^2)).
a(n) = (1/544)*(-221 - 68*(-1)^n + 2^(-1-n)*((2533-611*sqrt(17))*(3-sqrt(17))^n + (3+sqrt(17))^n*(2533+611*sqrt(17))) - 68*(1+n)).
(End)
EXAMPLE
Some solutions for n=4:
..1..1....1..1....1..0....0..0....1..0....0..1....1..0....0..1....1..0....0..0
..1..0....0..1....0..0....1..1....1..1....1..1....1..0....1..0....1..1....0..0
..0..1....0..1....1..1....1..0....1..0....0..0....1..1....1..1....0..0....0..1
..1..1....0..1....1..0....1..0....1..1....1..0....1..0....0..0....1..1....1..1
..0..0....0..1....1..0....1..0....1..0....0..1....0..0....1..1....1..1....0..0
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jan 11 2014
STATUS
approved