A209102 Number of 3 X n 0..2 arrays with new values 0..2 introduced in row major order and no element equal to more than one of its immediate leftward or upward or right-upward antidiagonal neighbors.

5, 82, 1326, 20928, 329064, 5171088, 81254376, 1276752432, 20061624144, 315228486048, 4953188212416, 77829494407872, 1222935603647424, 19215999064449408, 301941180717342336, 4744404717684160512

Offset: 1

Author

R. H. Hardin, Mar 05 2012

Keywords

• nonn

Comments

Row 3 of A209100.

Examples

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

Links

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

Crossrefs

Cf. A209100.

Formula

Empirical: a(n) = 22*a(n-1) - 110*a(n-2) + 180*a(n-3) - 60*a(n-4) for n>5.

Empirical g.f.: x*(5 - 28*x + 72*x^2 - 124*x^3 + 48*x^4) / (1 - 22*x + 110*x^2 - 180*x^3 + 60*x^4). - Colin Barker, Jul 08 2018