A233254 Number of n X 6 0..5 arrays with no element x(i,j) adjacent to itself or value 5-x(i,j) horizontally or antidiagonally, top left element zero, and 1 appearing before 2 3 and 4, and 2 appearing before 3 in row major order (unlabelled 6-colorings with no clashing color pairs).

136, 166400, 220626944, 294517735424, 393427728465920, 525597937107992576, 702177183940808278016, 938080982436565861007360, 1253239344772433062871957504, 1674278572660580852636051308544

Offset: 1

Author

R. H. Hardin, Dec 06 2013

Keywords

• nonn

Examples

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

Links

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

Crossrefs

Column 6 of A233256.

Formula

Empirical: a(n) = 1664*a(n-1) - 471040*a(n-2) + 44826624*a(n-3) - 1358954496*a(n-4).

Empirical g.f.: 8*x*(17 - 7488*x + 974848*x^2 - 40108032*x^3) / ((1 - 64*x)*(1 - 1600*x + 368640*x^2 - 21233664*x^3)). - Colin Barker, Oct 11 2018