OFFSET
1,1
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = 2*n^2 + 24*n + 52.
Conjectures from Colin Barker, Sep 02 2018: (Start)
G.f.: 2*x*(39 - 63*x + 26*x^2) / (1 - x)^3.
a(n) = 3*a(n-1) - 3*a(n-2) + a(n-3) for n>3.
(End)
EXAMPLE
Some solutions for n=3:
..1..0..0..0....1..0..0..0....1..1..0..1....1..0..1..0....1..0..0..0
..0..0..0..0....1..0..0..1....0..0..0..1....0..0..1..0....1..0..0..0
..0..0..0..0....1..0..0..1....0..0..0..1....0..0..1..0....1..0..0..0
..0..0..0..1....0..0..0..1....0..0..0..1....0..0..1..0....0..0..1..1
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Apr 14 2013
STATUS
approved