OFFSET
1,2
COMMENTS
Column 5 of A229510.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = 30*a(n-1) - 225*a(n-2) - 540*a(n-3) + 8748*a(n-4) - 9720*a(n-5) - 72900*a(n-6) + 174960*a(n-7) - 104976*a(n-8) for n > 9.
Empirical g.f.: 192*x^2*(8 - 78*x - 63*x^2 + 2187*x^3 - 3348*x^4 - 14418*x^5 + 37908*x^6 - 23328*x^7) / ((1 - 15*x + 18*x^2)^2*(1 - 18*x^2)^2). - Colin Barker, Jun 16 2017
EXAMPLE
Some solutions for n=3:
0 1 1 0 1 0 1 0 1 1 0 0 1 0 1 0 1 1 2 1
2 2 2 0 1 2 1 2 0 2 2 2 2 2 0 0 2 2 0 1
0 1 1 2 2 2 0 2 1 2 0 1 1 1 1 0 1 1 0 1
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Sep 25 2013
STATUS
approved