OFFSET
1,2
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = 2*a(n-1) - a(n-2) + 5*a(n-3) + a(n-4) + 6*a(n-5) + 7*a(n-6) + a(n-7) + 3*a(n-8) + 3*a(n-9) - 3*a(n-10) - 4*a(n-11) - a(n-12).
Empirical g.f.: x*(1 + 3*x + 7*x^2 + 5*x^3 + 12*x^4 + 8*x^5 + 4*x^6 + 6*x^7 - 7*x^9 - 5*x^10 - x^11) / ((1 + x^2 + x^3)*(1 - 2*x - 4*x^3 + x^4 - 2*x^5 - 4*x^6 + 3*x^8 + x^9)). - Colin Barker, Feb 23 2019
EXAMPLE
Some solutions for n=7:
..0..1..1. .1..1..0. .0..0..0. .0..1..0. .0..0..0. .0..0..1. .0..1..0
..0..1..0. .1..0..0. .1..1..0. .1..1..1. .1..1..0. .1..1..1. .1..1..1
..0..0..0. .0..0..1. .1..0..0. .0..1..0. .1..0..0. .1..0..0. .0..1..0
..1..1..0. .0..1..1. .0..0..1. .1..1..0. .0..0..0. .0..1..1. .1..1..0
..1..0..0. .0..0..0. .0..1..1. .0..0..0. .1..1..0. .0..1..0. .0..0..1
..0..1..0. .1..1..0. .0..0..0. .0..0..0. .1..0..0. .1..1..0. .1..1..1
..1..1..0. .1..0..0. .0..0..0. .0..0..0. .0..0..0. .0..0..0. .1..0..0
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Dec 15 2017
STATUS
approved