A233176 Number of 3 X n 0..5 arrays with no element x(i,j) adjacent to itself or value 5-x(i,j) horizontally, diagonally 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).

11, 80, 2688, 78336, 2469888, 76447744, 2385772544, 74291609600, 2315406802944, 72144847372288, 2248141575290880, 70053467808333824, 2182930872087347200, 68021929516908675072, 2119621843032249204736, 66049216835347669843968

Offset: 1

Author

R. H. Hardin, Dec 05 2013

Keywords

• nonn

Examples

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

Links

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

Crossrefs

Row 3 of A233174.

Formula

Empirical: a(n) = 32*a(n-1) + 64*a(n-2) - 3072*a(n-3) + 8192*a(n-4) for n>5.

Empirical g.f.: x*(11 - 272*x - 576*x^2 + 20992*x^3 - 53248*x^4) / ((1 - 8*x)*(1 - 24*x - 256*x^2 + 1024*x^3)). - Colin Barker, Oct 10 2018