A223348 3 X 3 X 3 triangular graph without horizontal edges coloring a rectangular array: number of n X 4 0..5 arrays where 0..5 label nodes of a graph with edges 0,1 0,2 1,3 1,4 2,4 2,5 and every array movement to a horizontal or vertical neighbor moves along an edge of this graph.

60, 1076, 20836, 405988, 7918948, 154482340, 3013692516, 58792282660, 1146943179236, 22375024222628, 436500886445412, 8515433203445028, 166122463695945956, 3240783209292085412, 63222490059635217508

Offset

1,1

Comments

Column 4 of A223352.

Links

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

Formula

Empirical: a(n) = 23*a(n-1) - 66*a(n-2) - 52*a(n-3) + 208*a(n-4) + 32*a(n-5) - 128*a(n-6).

Empirical g.f.: 4*x*(1 - 4*x)*(15 - 16*x - 52*x^2 + 16*x^3 + 32*x^4) / (1 - 23*x + 66*x^2 + 52*x^3 - 208*x^4 - 32*x^5 + 128*x^6). - Colin Barker, Aug 19 2018

Example

Some solutions for n=3:
..1..4..1..3....2..0..1..0....1..4..2..4....5..2..0..1....4..2..4..2
..4..2..0..1....4..2..0..1....0..2..4..2....2..0..1..3....1..4..2..4
..1..0..1..0....1..4..1..3....2..0..2..4....0..1..0..1....4..2..0..2

Crossrefs

Cf. A223352.

Sequence in context: A189607 A223213 A271651 * A305545 A056352 A056346

Adjacent sequences: A223345 A223346 A223347 * A223349 A223350 A223351

Keyword

nonn

Author

R. H. Hardin, Mar 19 2013

Status

approved