OFFSET
1,3
COMMENTS
Column 1 of A229479.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = 8*a(n-1) - 22*a(n-2) + 24*a(n-3) - 9*a(n-4) for n>6.
Conjectures from Colin Barker, Mar 16 2018: (Start)
G.f.: x^2*(1 - 6*x + 12*x^2 - 8*x^3 + 3*x^4) / ((1 - x)^2*(1 - 3*x)^2).
a(n) = (27+3^n) * (n-1) / 54 for n>2.
(End)
EXAMPLE
All solutions for n=4:
0 0 0 0 0 0
0 1 1 1 1 0
1 0 1 2 1 1
0 0 2 2 0 2
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Sep 24 2013
STATUS
approved