A199650 Number of nX3 0..2 arrays with values 0..2 introduced in row major order and each element equal to no more than two horizontal and vertical neighbors.

5, 113, 2584, 59212, 1357484, 31120632, 713445976, 16355879648, 374961537040, 8596061907680, 197066293538400, 4517780870646656, 103570953858672192, 2374383085485820032, 54433167085958461312, 1247890324488906825728

Offset: 1

Author

R. H. Hardin Nov 08 2011

Keywords

• nonn

Comments

Column 3 of A199655

Examples

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

Links

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

Formula

Empirical: a(n) = 21*a(n-1) +44*a(n-2) +8*a(n-3) -96*a(n-4) -364*a(n-5) -264*a(n-6) +256*a(n-7) +288*a(n-8) +64*a(n-9) for n>10