OFFSET
1,2
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = 7*a(n-1) - 5*a(n-2) - 25*a(n-3) + 47*a(n-4) - 4*a(n-5) - 100*a(n-6) + 104*a(n-7) - 36*a(n-8) + 4*a(n-9).
Empirical g.f.: 2*x^2*(1 - 6*x + 6*x^2 + 7*x^3 - 15*x^4 + 22*x^5 - 12*x^6 + 2*x^7) / (1 - 7*x + 5*x^2 + 25*x^3 - 47*x^4 + 4*x^5 + 100*x^6 - 104*x^7 + 36*x^8 - 4*x^9). - Colin Barker, Sep 25 2018
EXAMPLE
All solutions for n=3:
..0..1....0..3
..3..2....1..2
..0..1....0..3
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Nov 02 2013
STATUS
approved