OFFSET
1,1
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = 12*a(n-1) - 36*a(n-2) + 32*a(n-3) - 16*a(n-4).
Empirical g.f.: 2*x*(1 - 2*x)*(7 - 6*x + 4*x^2) / (1 - 12*x + 36*x^2 - 32*x^3 + 16*x^4). - Colin Barker, Sep 14 2018
EXAMPLE
Some solutions for n=3:
0 0 1 2 3 2 0 1 1 1 2 2 2 0 2 1 2 3 1 1
1 0 3 1 1 1 1 0 1 2 1 2 1 0 0 1 2 3 3 3
2 1 2 1 2 1 1 1 1 0 0 2 1 2 2 1 3 1 3 3
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Sep 21 2013
STATUS
approved