A163697 Number of nX4 binary arrays with all 1s connected, a path of 1s from top row to lower right corner, and no 1 having more than two 1s adjacent

4, 21, 80, 259, 775, 2223, 6336, 17796, 48912, 131828, 350506, 923197, 2413779, 6272766, 16221462, 41787691, 107324054, 274986699, 703245913, 1795790220, 4580304063, 11671650321, 29720454413

Offset

1,1

Links

Table of n, a(n) for n=1..23.

Example

All solutions for n=2
...0.0.0.1...0.0.0.1...0.0.1.1...0.0.1.1...0.1.1.1...0.0.1.0...0.1.1.0
...0.0.0.1...0.0.1.1...0.0.0.1...0.0.1.1...0.0.0.1...0.0.1.1...0.0.1.1
------
...1.1.1.0...0.1.1.1...1.1.1.1...1.1.1.0...0.1.1.1...1.1.1.1...0.0.0.1
...0.0.1.1...0.1.0.1...0.0.0.1...1.0.1.1...1.1.0.1...1.0.0.1...0.1.1.1
------
...0.1.0.0...0.1.0.1...1.1.0.0...1.1.0.1...0.0.0.1...1.0.0.0...1.0.0.1
...0.1.1.1...0.1.1.1...0.1.1.1...0.1.1.1...1.1.1.1...1.1.1.1...1.1.1.1

Crossrefs

Sequence in context: A192429 A354172 A280434 * A134424 A348621 A277794

Adjacent sequences: A163694 A163695 A163696 * A163698 A163699 A163700

Keyword

nonn

Author

R. H. Hardin Aug 03 2009

Status

approved