A190828 Number of permutations of 3 copies of 1..n introduced in order 1..n with no element equal to another within a distance of 3

0, 0, 0, 1, 436, 105876, 27361381, 8448460856, 3162324496414

Offset

1,5

Links

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

Example

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

Crossrefs

Sequence in context: A278176 A243233 A216988 * A084293 A237939 A088893

Adjacent sequences: A190825 A190826 A190827 * A190829 A190830 A190831

Keyword

nonn

Author

R. H. Hardin May 21 2011

Status

approved