OFFSET
1,1
COMMENTS
Row 4 of A208637.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = 5*a(n-1) - 9*a(n-2) + 7*a(n-3) - 2*a(n-4) for n>5.
Conjectures from Colin Barker, Jul 05 2018: (Start)
G.f.: x*(8 - 6*x - 3*x^2 + 2*x^4) / ((1 - x)^3*(1 - 2*x)).
a(n) = (-42 + 35*2^n - 13*n - n^2) / 2 for n>1.
(End)
EXAMPLE
Some solutions for n=4:
..0..1..0..1....0..1..0..1....0..0..0..1....0..1..1..1....0..0..1..0
..1..0..1..0....0..1..0..0....1..1..0..0....1..0..0..0....1..0..1..1
..0..1..0..1....0..1..1..1....0..1..1..1....0..1..1..1....0..1..0..1
..0..1..0..1....1..0..0..1....0..0..0..0....1..0..0..0....0..1..0..0
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Feb 29 2012
STATUS
approved