OFFSET
1,1
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) + 10*a(n-3) - 6*a(n-4) + a(n-5) for n>7.
Empirical g.f.: x*(4 + 7*x - 56*x^2 + 106*x^3 - 119*x^4 + 63*x^5 - 9*x^6) / ((1 - x)*(1 - 4*x + 5*x^2 - 5*x^3 + x^4)). - Colin Barker, Jan 31 2019
EXAMPLE
Some solutions for n=4:
..0..1..2..0. .0..1..0..2. .0..1..0..1. .0..1..2..1. .0..1..0..1
..1..2..0..2. .1..0..2..1. .1..0..2..0. .2..0..1..2. .1..0..2..0
..2..0..1..0. .0..2..1..2. .0..2..1..2. .0..1..2..0. .0..2..1..2
..0..1..0..1. .2..1..2..1. .2..0..2..1. .1..2..0..2. .2..1..2..1
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jul 09 2016
STATUS
approved