

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


1



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

1,3


COMMENTS



LINKS



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



KEYWORD

nonn


AUTHOR



STATUS

approved



