A183275 Half the number of nXnXn triangular binary arrays with each element having no more than two neighbors equal to itself

1, 4, 16, 67, 277, 1025, 3407, 10265, 28589, 74945, 187583, 453167, 1065257, 2451317, 5546819, 12383627, 27347117, 59851121, 130009223, 280620167, 602424305, 1287187757, 2739013259, 5807246915, 12272861813, 25862365481

Offset

1,2

Links

Table of n, a(n) for n=1..26.

Example

Some solutions for 5X5X5 with a(1,1)=0
......0..........0..........0..........0..........0..........0..........0
.....1.1........0.1........1.1........1.1........1.1........1.0........1.1
....1.0.1......1.1.0......1.0.0......1.0.1......0.0.1......1.0.1......0.0.0
...0.1.0.1....1.0.0.1....0.1.1.1....1.0.1.0....1.1.0.0....0.0.1.0....0.1.1.0
..1.0.1.1.0..1.0.1.1.0..1.0.0.0.1..0.1.1.0.0..1.0.1.1.0..1.1.1.0.0..1.0.1.0.1

Crossrefs

Sequence in context: A151242 A218645 A273582 * A024551 A261048 A091153

Adjacent sequences: A183272 A183273 A183274 * A183276 A183277 A183278

Keyword

nonn

Author

R. H. Hardin Jan 03 2011

Status

approved