OFFSET
1,1
COMMENTS
Column 1 of A262274.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = 3*a(n-1) - 3*a(n-2) + 3*a(n-3) - 2*a(n-4).
Conjectures from Colin Barker, Feb 21 2018: (Start)
G.f.: x*(2 - 2*x + x^2 - 2*x^3) / ((1 - x)*(1 - 2*x)*(1 + x^2)).
a(n) = 1/2 + 2^(2+n)/5 - (1/20-i/20)*((1+2*i)*(-i)^n + (2+i)*i^n) where i=sqrt(-1).
(End)
EXAMPLE
Some solutions for n=4:
..0..0..0....0..0..0....1..0..1....1..0..1....0..0..0....0..0..0....0..0..0
..1..0..1....0..0..0....0..0..0....1..0..1....0..0..0....0..0..0....1..0..1
..1..0..1....0..0..0....1..0..1....0..0..0....1..0..1....0..0..0....1..0..1
..1..0..1....1..0..1....0..0..0....1..0..1....1..0..1....0..0..0....0..0..0
..1..0..1....0..0..0....0..0..0....1..0..1....1..0..1....0..0..0....0..0..0
..0..0..0....1..0..1....0..0..0....1..0..1....1..0..1....0..0..0....1..0..1
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Sep 17 2015
STATUS
approved