A190829 Number of permutations of 3 copies of 1..n introduced in order 1..n with no element equal to another within a distance of 4

0, 0, 0, 0, 1, 1744, 930776, 403365340, 183903095593

Offset

1,6

Links

Table of n, a(n) for n=1..9.

Example

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

Crossrefs

Sequence in context: A090837 A250466 A260014 * A038010 A362875 A324710

Adjacent sequences: A190826 A190827 A190828 * A190830 A190831 A190832

Keyword

nonn

Author

R. H. Hardin May 21 2011

Status

approved