A208388 Number of n X 4 0..2 arrays with new values 0..2 introduced in row major order and no element equal to more than two of its immediate leftward or upward or right-upward antidiagonal neighbors.

14, 1017, 76806, 5800644, 438083928, 33085555344, 2498731184736, 188712490047552, 14252194920963456, 1076373164351510784, 81291281473560135168, 6139387958073915884544, 463666998680569442359296

Offset: 1

Author

R. H. Hardin, Feb 25 2012

Keywords

• nonn

Comments

Column 4 of A208392.

Examples

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

Links

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

Crossrefs

Cf. A208392.

Formula

Empirical: a(n) = 76*a(n-1) - 36*a(n-2) for n>3.

Empirical g.f.: x*(14 - 47*x + 18*x^2) / (1 - 76*x + 36*x^2). - Colin Barker, Jul 02 2018