OFFSET
1,1
COMMENTS
Column 3 of A269537.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = 7*a(n-1) - 9*a(n-2) - 23*a(n-3) + 31*a(n-4) + 33*a(n-5).
Empirical g.f.: 2*x*(2 - 6*x - 8*x^2 + 19*x^3 + 17*x^4) / ((1 - 3*x)*(1 - 4*x - 3*x^2 + 14*x^3 + 11*x^4)). - Colin Barker, Mar 21 2018
EXAMPLE
Some solutions for n=9:
..2. .1. .0. .0. .3. .0. .1. .2. .1. .2. .0. .1. .1. .0. .0. .1
..1. .3. .3. .0. .0. .2. .2. .2. .0. .0. .3. .2. .3. .3. .2. .2
..0. .0. .2. .1. .3. .3. .0. .0. .3. .1. .0. .0. .1. .3. .0. .1
..2. .3. .2. .1. .2. .2. .1. .3. .1. .2. .0. .2. .0. .0. .3. .3
..2. .0. .3. .0. .0. .0. .0. .2. .0. .3. .2. .3. .3. .3. .2. .3
..3. .2. .0. .0. .3. .1. .0. .0. .2. .0. .3. .1. .3. .0. .0. .0
..1. .1. .3. .2. .2. .0. .3. .3. .2. .3. .2. .2. .1. .2. .1. .1
..1. .2. .0. .3. .3. .0. .1. .2. .0. .2. .1. .2. .2. .1. .2. .0
..3. .3. .3. .0. .0. .1. .3. .3. .3. .2. .2. .0. .2. .2. .1. .2
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Feb 29 2016
STATUS
approved