OFFSET
1,1
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = a(n-1) +3*a(n-2) -2*a(n-3) -3*a(n-4) +a(n-5) +a(n-6).
Empirical: a(n) = a(n-1) + a(n-2) + (n+1)(3-(-1)^(n+1))/4. - Chris in the Sequence Fans Mailing List.
Empirical g.f.: x*(2 + 4*x - 2*x^2 - 3*x^3 + x^4 + x^5) / ((1 - x)^2*(1 + x)^2*(1 - x - x^2)). - Colin Barker, Jan 30 2019
EXAMPLE
Some solutions for n=5:
..1..0. .1..1. .1..1. .0..1. .0..1. .1..0. .1..0. .0..1. .1..0. .0..1
..1..0. .0..0. .0..0. .0..0. .0..1. .1..0. .0..1. .0..1. .0..0. .0..1
..0..1. .0..1. .0..1. .1..1. .0..1. .0..1. .0..1. .1..0. .1..1. .0..1
..0..1. .0..1. .0..0. .0..0. .0..1. .0..0. .1..0. .1..0. .0..0. .0..0
..1..0. .0..1. .1..1. .1..1. .0..1. .1..1. .1..0. .0..1. .1..1. .1..1
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, May 11 2016
STATUS
approved