OFFSET
1,1
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = 2*a(n-1) + 20*a(n-2) + 43*a(n-3) - 20*a(n-4) - 92*a(n-5) - 176*a(n-6) - 16*a(n-7) - 16*a(n-8) + 64*a(n-9) for n>10.
Empirical g.f.: x*(32 + x - 381*x^2 - 1068*x^3 - 64*x^4 + 1304*x^5 + 3392*x^6 + 384*x^7 + 496*x^8 - 1216*x^9) / (1 - 2*x - 20*x^2 - 43*x^3 + 20*x^4 + 92*x^5 + 176*x^6 + 16*x^7 + 16*x^8 - 64*x^9). - Colin Barker, Feb 01 2019
EXAMPLE
Some solutions for n=4:
..0..0..1..1. .0..1..2..0. .0..0..1..1. .0..1..2..2. .0..0..0..1
..1..2..0..0. .2..0..1..1. .2..2..2..0. .2..0..0..1. .2..2..2..0
..0..1..1..2. .1..2..2..0. .0..1..1..2. .1..1..2..0. .0..1..1..2
..2..2..0..1. .0..1..1..2. .2..0..0..1. .0..0..1..2. .2..0..0..1
..1..1..2..2. .2..2..0..1. .1..2..2..2. .2..2..0..0. .1..2..2..0
..0..0..1..1. .1..1..2..0. .0..1..1..1. .1..1..2..2. .0..0..1..2
..2..2..0..0. .0..0..1..1. .2..2..0..0. .0..0..1..1. .2..2..0..1
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jul 19 2016
STATUS
approved