OFFSET
1,1
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = 10*a(n-1) - a(n-2) - 80*a(n-3) + 133*a(n-4) - 49*a(n-5) - 16*a(n-6) + 4*a(n-7) for n>9.
Empirical g.f.: 4*x*(2 + 16*x - 98*x^2 - 77*x^3 + 841*x^4 - 1108*x^5 + 434*x^6 - 72*x^7 + 24*x^8) / ((1 - x)*(1 - 9*x - 8*x^2 + 72*x^3 - 61*x^4 - 12*x^5 + 4*x^6)). - Colin Barker, Jan 30 2019
EXAMPLE
Some solutions for n=4:
..0..1..0..0. .0..1..0..2. .0..1..2..1. .0..1..0..2. .0..1..2..2
..2..0..1..2. .1..0..1..0. .1..0..1..2. .1..0..1..0. .1..0..1..0
..1..1..0..1. .2..1..2..1. .2..1..2..1. .0..2..0..1. .0..1..0..1
..2..0..2..0. .1..0..1..0. .0..0..1..2. .1..0..2..0. .2..0..1..0
..1..2..0..2. .2..1..0..1. .2..1..2..1. .2..2..0..1. .0..2..0..2
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jul 03 2016
STATUS
approved