A163725 Number of nX4 binary arrays with all 1s connected, a path of 1s from left column to right column, and no 1 having more than two 1s adjacent

1, 16, 108, 531, 2119, 7338, 23330, 70369, 204461, 576824, 1589880, 4304373, 11495305, 30376964, 79611466, 207289163, 536963245

Offset

1,2

Links

Table of n, a(n) for n=1..17.

Example

All solutions for n=2
...1.1.1.1...1.1.1.1...1.1.1.1...1.1.1.1...0.0.0.0...0.0.0.1...1.0.0.0
...0.0.0.0...0.0.0.1...1.0.0.0...1.0.0.1...1.1.1.1...1.1.1.1...1.1.1.1
------
...1.0.0.1...1.1.0.0...1.1.0.1...1.1.1.0...1.1.1.0...0.0.1.1...1.0.1.1
...1.1.1.1...0.1.1.1...0.1.1.1...0.0.1.1...1.0.1.1...1.1.1.0...1.1.1.0
------
...0.1.1.1...0.1.1.1
...1.1.0.0...1.1.0.1

Crossrefs

Sequence in context: A224411 A260357 A056001 * A269188 A165558 A337391

Adjacent sequences: A163722 A163723 A163724 * A163726 A163727 A163728

Keyword

nonn

Author

R. H. Hardin Aug 03 2009

Status

approved