OFFSET
1,1
COMMENTS
Column 1 of A197442.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..200
FORMULA
Empirical: a(n) = a(n-1) +2*a(n-2) +3*a(n-3) +2*a(n-4) for n>5.
Empirical g.f.: x*(3 + 3*x - 2*x^2 - 3*x^3 - 6*x^4) / (1 - x - 2*x^2 - 3*x^3 - 2*x^4). - Colin Barker, May 12 2018
EXAMPLE
Some solutions for n=4:
0 2 1 0 2 1 1 1 2 2 1 2 0 0 0 0
1 0 0 2 1 2 0 2 0 0 0 1 1 2 2 2
1 0 2 0 1 0 2 0 2 1 1 2 1 1 2 0
2 1 1 1 2 1 0 2 0 0 0 0 0 2 1 2
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Oct 15 2011
STATUS
approved