A223443 4-level binary fanout graph coloring a rectangular array: number of n X 2 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.

28, 104, 408, 1616, 6432, 25664, 102528, 409856, 1638912, 6554624, 26216448, 104861696, 419438592, 1677737984, 6710919168, 26843611136, 107374313472, 429496991744, 1717987442688, 6871948722176, 27487792791552, 109951166971904

Offset

1,1

Comments

Column 2 of A223449.

Links

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

Formula

Empirical: a(n) = 6*a(n-1) - 8*a(n-2) for n>3.

Conjectures from Colin Barker, Aug 20 2018: (Start)

G.f.: 4*x*(7 - 16*x + 2*x^2) / ((1 - 2*x)*(1 - 4*x)).

a(n) = 2^(n-2) * (4+25*2^n) for n>1.

(End)

Example

Some solutions for n=3:
.10.13....1..0....9.11....4..7...10..2...12..9....1..3....1..4....3..5....4..1
.13.10....3..1....2..9....8..4...14.10....9.12....3..6....3..1....6..3....1..0
.10.14....5..3....0..2....4..8...10.13....2..9....1..3....1..3....3..1....4..1

Crossrefs

Cf. A223449.

Sequence in context: A168254 A219380 A263200 * A201469 A010016 A256647

Adjacent sequences: A223440 A223441 A223442 * A223444 A223445 A223446

Keyword

nonn

Author

R. H. Hardin, Mar 20 2013

Status

approved