OFFSET
1,1
COMMENTS
Column 3 of A269494.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = 9*a(n-1) - 24*a(n-2) + 9*a(n-3) + 26*a(n-4) + 3*a(n-5).
Empirical g.f.: 2*x*(2 - 10*x + 8*x^2 + 11*x^3 + x^4) / ((1 - 3*x)*(1 - 6*x + 6*x^2 + 9*x^3 + x^4)). - Colin Barker, Mar 21 2018
EXAMPLE
Some solutions for n=6:
..1. .2. .2. .0. .0. .3. .0. .0. .3. .2. .1. .2. .3. .3. .2. .0
..2. .2. .1. .3. .1. .3. .2. .2. .3. .2. .0. .1. .2. .2. .0. .0
..2. .0. .2. .3. .0. .3. .1. .1. .2. .2. .3. .1. .1. .1. .1. .2
..2. .3. .3. .1. .1. .2. .3. .3. .3. .1. .1. .0. .3. .0. .2. .3
..0. .2. .0. .2. .3. .3. .1. .1. .1. .2. .2. .1. .1. .2. .0. .0
..1. .3. .0. .3. .0. .2. .2. .3. .3. .3. .2. .2. .0. .2. .3. .3
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Feb 28 2016
STATUS
approved