A190920 Number of permutations of n copies of 1..5 introduced in order 1..5 with no element equal to another within a distance of 1.

1, 329, 163386, 98371884, 66218360625, 47940557125969, 36533294879349056, 28920026907938624194, 23575497690601916022516, 19672658572012343899666292, 16730974132035148942028759656, 14455459908454408519322566567054

Offset

1,2

Links

Seiichi Manyama, Table of n, a(n) for n = 1..334 (terms 1..55 from R. H. Hardin)

Formula

a(n) ~ 25 * sqrt(5) * 2^(10*n-7) / (27 * Pi^2 * n^2). - Vaclav Kotesovec, Nov 24 2018

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....1....3....3....3....3....3....3....3
..4....4....2....1....4....4....4....4....3....4....4....4....1....4....4....4
..1....5....4....4....1....5....3....5....4....5....3....5....4....3....2....5
..5....3....5....2....5....2....4....4....5....2....2....3....5....2....3....2
..2....2....4....3....4....1....5....5....2....4....5....5....4....5....5....5
..5....1....3....5....2....3....1....1....4....3....1....4....2....1....4....4
..3....4....5....4....3....4....5....3....5....5....5....1....5....4....1....3
..4....5....1....5....5....5....2....2....3....1....4....2....3....5....5....1

Crossrefs

Column k=5 of A322013.

Cf. A000012 (b=2), A190917 (b=3), A190918 (b=4), A190923 (b=6), A190927 (b=7), A190932 (b=8), A321987 (b=9).

Sequence in context: A231362 A202010 A265195 * A145274 A174848 A300009

Adjacent sequences: A190917 A190918 A190919 * A190921 A190922 A190923

Keyword

nonn

Author

R. H. Hardin, May 23 2011

Status

approved