A221453 Number of 0..n arrays of length n with each element unequal to at least one neighbor, with new values introduced in 0..n order

0, 1, 2, 7, 25, 102, 456, 2219, 11640, 65364, 390646, 2472719, 16508791, 115839661, 851634863, 6542134884, 52384882759, 436290809772, 3772143122161, 33797290492507, 313304547351868, 3000631062271288, 29651208549845055

Offset

1,3

Comments

Diagonal of A221459

Links

R. H. Hardin, Table of n, a(n) for n = 1..182

Example

Some solutions for n=6
..0....0....0....0....0....0....0....0....0....0....0....0....0....0....0....0
..1....1....1....1....1....1....1....1....1....1....1....1....1....1....1....1
..0....2....1....0....2....2....1....0....2....2....0....1....0....1....1....1
..2....1....2....1....3....0....2....2....1....3....2....2....1....2....2....0
..2....3....1....1....0....0....2....3....2....2....1....2....2....1....3....0
..3....4....2....2....3....3....1....0....3....0....2....0....0....3....0....1

Crossrefs

Sequence in context: A221456 A221457 A221458 * A097597 A150512 A150513

Adjacent sequences: A221450 A221451 A221452 * A221454 A221455 A221456

Keyword

nonn

Author

R. H. Hardin Jan 17 2013

Status

approved