OFFSET
1,1
COMMENTS
Column 3 of A223263.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = 38*a(n-1) - 129*a(n-2).
Conjectures from Colin Barker, Aug 18 2018: (Start)
G.f.: 5*x*(5 - 21*x) / (1 - 38*x + 129*x^2).
a(n) = (5*((19-2*sqrt(58))^n*(-41+7*sqrt(58)) + (19+2*sqrt(58))^n*(41+7*sqrt(58)))) / (86*sqrt(58)).
(End)
EXAMPLE
Some solutions for n=3:
..0..1..3....0..6..2....0..5..6....0..1..8....0..7..1....0..7..1....0..2..8
..6..2..8....5.10..6....5.10..5....1..0..2....6..5..0....7..1..3....1..8..4
..2..0..2...10..6..2....7..5..7....7..5..0....2..0..1....5..7.11....8..4..8
Vertex neighbors:
0.->.1.2.5.6.7
1.->.0.2.3.7.8
2.->.0.1.4.6.8
3.->.1.7.8.9.11
4.->.2.6.8.9.10
5.->.0.6.7.10.11
6.->.0.2.4.5.10
7.->.0.1.3.5.11
8.->.1.2.3.4.9
9.->.3.4.8.10.11
10.->.4.5.6.9.11
11.->.3.5.7.9.10
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Mar 19 2013
STATUS
approved