A263662 Number of length n arrays of permutations of 0..n-1 with each element moved by -4 to 4 places and with no two consecutive increases or two consecutive decreases.

1, 2, 4, 10, 32, 95, 208, 486, 1064, 2560, 6000, 14636, 33680, 81608, 187488, 454456, 1046368, 2537664, 5840768, 14162704, 32593088, 79031008, 181889408, 441050016, 1015068544, 2461353728, 5664729088, 13735909824, 31612832000, 76655260288

Offset

1,2

Comments

Column 4 of A263666.

Links

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

Formula

Empirical: a(n) = 4*a(n-2) +6*a(n-4) +16*a(n-6) -8*a(n-10) for n>20

Example

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

Crossrefs

Cf. A263666.

Sequence in context: A005269 A070900 A296003 * A151400 A363138 A365516

Adjacent sequences: A263659 A263660 A263661 * A263663 A263664 A263665

Keyword

nonn

Author

R. H. Hardin, Oct 23 2015

Status

approved