A199143 Number of nX2 0..3 arrays with values 0..3 introduced in row major order and each element equal to one or two horizontal and vertical neighbors

1, 3, 13, 65, 393, 2539, 16866, 113432, 766473, 5188597, 35148945, 238173743, 1614066774, 10938730576, 74134306725, 502428413393, 3405102418833, 23077383280435, 156402287318610, 1059984943413152, 7183834447992225

Offset

1,2

Comments

Column 2 of A199149

Links

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

Formula

Empirical: a(n) = 7*a(n-1) +2*a(n-2) -16*a(n-3) -49*a(n-4) -35*a(n-5) +56*a(n-6) +54*a(n-7) +45*a(n-8) -27*a(n-9) for n>11

Example

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

Crossrefs

Sequence in context: A155867 A009102 A080227 * A002468 A198663 A156181

Adjacent sequences: A199140 A199141 A199142 * A199144 A199145 A199146

Keyword

nonn

Author

R. H. Hardin Nov 03 2011

Status

approved