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

Author

R. H. Hardin Jan 17 2013

Keywords

• nonn

Comments

Diagonal of A221459

Examples

			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
		

Links

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