A217886 Number of n element 1..n arrays with each element the minimum of 3 adjacent elements of a permutation of 1..n+2 of n+2 elements

1, 3, 11, 44, 192, 892, 4400, 23086, 129250, 773868, 4953208, 33778104, 244102608, 1858257232, 14822495192

Offset

1,2

Comments

Column 3 of A217891

Links

Table of n, a(n) for n=1..15.

Example

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

Crossrefs

Sequence in context: A151108 A256752 A018963 * A234627 A030815 A030880

Adjacent sequences: A217883 A217884 A217885 * A217887 A217888 A217889

Keyword

nonn

Author

R. H. Hardin Oct 14 2012

Status

approved