A223409 4 X 4 X 4 triangular graph without horizontal edges coloring a rectangular array: number of n X 2 0..9 arrays where 0..9 label nodes of a graph with edges 0,1 0,2 1,3 1,4 2,4 2,5 3,6 3,7 4,7 4,8 5,8 5,9 and every array movement to a horizontal or vertical neighbor moves along an edge of this graph.

24, 132, 780, 4664, 28060, 169124, 1020056, 6153860, 37128748, 224020376, 1351668764, 8155585924, 49208586616, 296911448452, 1791484795980, 10809344595640, 65220724455836, 393524597542756, 2374423335359192

Offset

1,1

Comments

Column 2 of A223415.

Links

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

Formula

Empirical: a(n) = 9*a(n-1) - 17*a(n-2) - 10*a(n-3) + 26*a(n-4) + 10*a(n-5).

Empirical g.f.: 4*x*(6 - 21*x + 32*x^3 + 10*x^4) / (1 - 9*x + 17*x^2 + 10*x^3 - 26*x^4 - 10*x^5). - Colin Barker, Aug 20 2018

Example

Some solutions for n=3:
..5..2....2..0....4..1....3..1....6..3....8..5....8..5....4..2....1..4....2..4
..8..4....0..1....7..4....1..0....3..1....4..8....4..2....8..4....0..2....4..8
..4..7....1..4....4..1....0..1....6..3....1..4....8..4....5..2....2..5....1..4

Crossrefs

Cf. A223415.

Sequence in context: A293365 A093699 A275405 * A205343 A267631 A305681

Adjacent sequences: A223406 A223407 A223408 * A223410 A223411 A223412

Keyword

nonn

Author

R. H. Hardin, Mar 20 2013

Status

approved