OFFSET
1,2
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = 3*a(n-1) + a(n-3) + 5*a(n-4) + a(n-7).
Empirical g.f.: x*(1 + 3*x^2 + x^5) / ((1 + x^2 + x^3)*(1 - 3*x - x^2 + x^3 - x^4)). - Colin Barker, Jan 07 2019
EXAMPLE
Some solutions for n=4:
..6..7..1..2..3....6..0..1..9..3....6.12.13.14..7...11.12.13..2..3
..0.12.13.14..4...11.12..2.14..4....0..1..2..3..4....0..1..6.14..4
..5.10.11..8..9....5.10..7..8.13....5.10.11..8..9....5.10..7..8..9
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Nov 12 2015
STATUS
approved