OFFSET
1,1
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = 2*a(n-1) + 15*a(n-2) + 55*a(n-3) + 69*a(n-4) + 8*a(n-5) - 50*a(n-6) + 14*a(n-7) + a(n-8) - a(n-9) for n>10.
Empirical g.f.: x*(12 + 39*x + 88*x^2 + 11*x^3 - 127*x^4 - 92*x^5 + 63*x^6 + 16*x^7 - 20*x^8 + x^9) / (1 - 2*x - 15*x^2 - 55*x^3 - 69*x^4 - 8*x^5 + 50*x^6 - 14*x^7 - x^8 + x^9). - Colin Barker, Feb 04 2019
EXAMPLE
Some solutions for n=4:
..0..1..2..2. .0..1..1..1. .0..0..1..2. .0..1..1..1. .0..0..1..2
..2..0..1..2. .0..0..0..1. .2..2..0..1. .2..0..0..0. .2..0..0..0
..1..2..0..0. .1..2..0..0. .1..1..2..0. .2..2..2..2. .2..2..2..0
..1..1..2..0. .1..2..1..2. .0..1..1..2. .0..1..1..2. .0..1..2..1
..0..0..1..2. .0..0..1..2. .2..2..0..1. .0..0..1..1. .0..0..0..1
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jul 26 2016
STATUS
approved