A223442 4-level binary fanout graph coloring a rectangular array: number of n X 1 0..14 arrays where 0..14 label nodes of a graph with edges 0,1 1,3 3,5 3,6 1,4 4,7 4,8 0,2 2,9 9,11 9,12 2,10 10,13 10,14 and every array movement to a horizontal or vertical neighbor moves along an edge of this graph.

15, 28, 66, 144, 336, 752, 1752, 3936, 9168, 20608, 48000, 107904, 251328, 564992, 1315968, 2958336, 6890496, 15490048, 36079104, 81106944, 188912640, 424681472, 989159424, 2223661056, 5179305984, 11643240448, 27119198208, 60964798464

Offset

1,1

Comments

Column 1 of A223449.

Links

R. H. Hardin, Table of n, a(n) for n = 1..210

Formula

Empirical: a(n) = 6*a(n-2) - 4*a(n-4).

Empirical g.f.: x*(3 + 2*x)*(5 + 6*x - 12*x^2) / (1 - 6*x^2 + 4*x^4). - Colin Barker, Aug 20 2018

Example

Some solutions for n=3:
.12...13....3....7....1....8....2....2....9....2....6....1....0....2...11....0
..9...10....1....4....0....4....0....9....2....0....3....0....2....9....9....2
..2...13....0....8....2....8....1...12...10....2....1....1....9...11....2....0

Crossrefs

Cf. A223449.

Sequence in context: A350045 A357278 A343067 * A121594 A163286 A022997

Adjacent sequences: A223439 A223440 A223441 * A223443 A223444 A223445

Keyword

nonn

Author

R. H. Hardin, Mar 20 2013

Status

approved