A198901 Number of n X 3 0..4 arrays with values 0..4 introduced in row major order and no element equal to any horizontal or vertical neighbor.

2, 33, 1211, 50384, 2125425, 89793204, 3794115705, 160319061892, 6774239755817, 286243775060868, 12095158053422201, 511077834439270724, 21595464215307153225, 912510860892666556164, 38557914891188891686425

Offset: 1

Author

R. H. Hardin, Oct 31 2011

Keywords

• nonn

Comments

Column 3 of A198906.

Examples

			Some solutions with values 0 to 4 for n=4:
..0..1..2....0..1..2....0..1..2....0..1..0....0..1..0....0..1..0....0..1..2
..1..0..3....1..3..1....2..3..1....1..0..2....2..3..2....2..0..3....2..3..1
..2..1..4....4..1..0....4..0..2....3..4..3....3..2..4....4..2..0....1..4..0
..4..0..3....2..0..2....0..1..3....1..2..1....2..1..0....3..0..4....3..0..4
		

Links

• R. H. Hardin, Table of n, a(n) for n = 1..200

Crossrefs

Cf. A198906.

Formula

Empirical: a(n) = 51*a(n-1) - 393*a(n-2) + 1013*a(n-3) - 902*a(n-4) + 232*a(n-5).

Empirical g.f.: x*(2 - 69*x + 314*x^2 - 434*x^3 + 139*x^4) / ((1 - x)*(1 - 5*x + 2*x^2)*(1 - 45*x + 116*x^2)). - Colin Barker, Mar 02 2018