A190924 Number of permutations of n copies of 1..6 introduced in order 1..6 with no element equal to another within a distance of 2

1, 1146, 2001240, 4336589521, 10691055854826, 28712861760925166, 81958815992936732932, 244852995292964593983615, 757831532841526180711756422, 2412699575781124816170722396128

Offset

1,2

Links

R. H. Hardin, Table of n, a(n) for n = 1..27

Example

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

Crossrefs

Sequence in context: A123697 A260977 A227478 * A196779 A180344 A031785

Adjacent sequences: A190921 A190922 A190923 * A190925 A190926 A190927

Keyword

nonn

Author

R. H. Hardin May 23 2011

Status

approved