A268456 Number of length-n 0..7 arrays with no adjacent pair x,x+1 followed at any distance by x+1,x.

8, 64, 505, 3977, 31276, 245626, 1926444, 15089356, 118040270, 922247248, 7196716310, 56092274904, 436681564144, 3395712755366, 26376195676360, 204653424502050, 1586213921445534, 12281469122143732, 94993604706706795

Offset

1,1

Comments

Column 7 of A268457.

Links

R. H. Hardin, Table of n, a(n) for n = 1..210

Example

Some solutions for n=5
..7....2....3....3....6....4....5....4....1....0....6....7....6....4....2....4
..6....5....2....6....5....4....1....1....6....2....1....4....5....1....4....1
..4....4....1....4....0....5....3....0....4....4....7....5....0....3....7....7
..5....4....1....5....1....0....4....7....3....2....2....3....7....4....3....0
..2....0....1....1....6....6....0....6....6....1....6....6....7....4....2....4

Crossrefs

Cf. A268457.

Sequence in context: A269605 A269466 A127426 * A126629 A250350 A171282

Adjacent sequences: A268453 A268454 A268455 * A268457 A268458 A268459

Keyword

nonn

Author

R. H. Hardin, Feb 04 2016

Status

approved