OFFSET
1,2
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = 4*a(n-3) + 2*a(n-4) + 2*a(n-5) - 2*a(n-9) - a(n-10).
Empirical g.f.: x^2*(4 + 2*x + x^2 - 2*x^6 - x^7) / ((1 + x + x^2 - x^3 - x^4)*(1 - x - 2*x^3 - x^5 - x^6)). - Colin Barker, Jan 08 2019
EXAMPLE
All solutions for n=4:
.12.13.14..2..3
..0..1..6..7..4
..5.10.11..8..9
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Nov 17 2015
STATUS
approved