A222440 Number of n X 4 0..3 arrays with entries increasing mod 4 by 0, 1 or 2 rightwards and downwards, starting with upper left zero.

27, 1029, 39285, 1500183, 57289767, 2187822609, 83550197745, 3190677470643, 121847980727187, 4653221950068669, 177700725073710285, 6786168386579878383, 259155281174281941087, 9896815984320245625609, 377947021506548282896905

Offset: 1

Author

R. H. Hardin, Feb 20 2013

Keywords

• nonn

Comments

Column 4 of A222444.

Examples

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

Links

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

Crossrefs

Cf. A222444.

Formula

Empirical: a(n) = 45*a(n-1) - 267*a(n-2) + 263*a(n-3).

Empirical g.f.: 3*x*(9 - 62*x + 63*x^2) / (1 - 45*x + 267*x^2 - 263*x^3). - Colin Barker, Mar 15 2018