OFFSET
1,1
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = 8*a(n-1) - 27*a(n-2) + 56*a(n-3) - 75*a(n-4) + 61*a(n-5) - 28*a(n-6) + 7*a(n-7) - a(n-8) for n>9.
Empirical g.f.: x*(12 - 70*x + 200*x^2 - 367*x^3 + 425*x^4 - 301*x^5 + 126*x^6 - 30*x^7 + 4*x^8) / ((1 - x)^3*(1 - 5*x + 9*x^2 - 13*x^3 + 4*x^4 - x^5)). - Colin Barker, Jan 31 2019
EXAMPLE
Some solutions for n=4:
..0..1..2..1. .0..1..2..0. .0..1..0..1. .0..1..2..1. .0..1..2..0
..1..2..0..1. .0..1..2..0. .1..2..0..1. .0..2..0..1. .1..2..0..1
..1..0..1..2. .1..2..0..1. .1..0..1..2. .1..2..1..2. .2..0..1..2
..2..0..1..2. .2..0..1..2. .2..0..2..0. .1..0..1..0. .0..1..2..0
..2..1..2..0. .2..1..2..0. .0..1..2..0. .2..0..2..0. .0..1..0..1
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jul 10 2016
STATUS
approved