OFFSET
1,1
COMMENTS
Row 4 of A208555.
It seems that all terms are squares. - Colin Barker, Mar 07 2018
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = 3*a(n-1) + 6*a(n-2) - 8*a(n-3).
Conjectures from Colin Barker, Mar 07 2018: (Start)
G.f.: 9*x*(1 + 6*x - 8*x^2) / ((1 - x)*(1 + 2*x)*(1 - 4*x)).
a(n) = (2^(n+1) + 1)^2 for n even.
a(n) = (2^(n+1) - 1)^2 for n odd.
(End)
EXAMPLE
Some solutions for n=4:
..0..1..1..1....1..0..1..1....0..1..1..1....1..0..1..0....0..1..0..0
..1..0..1..0....0..1..1..0....0..1..0..1....0..1..1..1....1..0..1..1
..0..1..0..0....1..0..1..1....0..1..1..0....1..0..1..0....0..1..0..0
..1..0..1..0....0..1..1..0....0..1..0..0....0..1..0..1....1..0..1..1
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Feb 28 2012
STATUS
approved