A190929 Number of permutations of n copies of 1..7 introduced in order 1..7 with no element equal to another within a distance of 3.

1, 4317, 27361381, 216956034178, 1979495929398725, 19864953170991117438, 213525202167474545255168, 2417277939494344003029244944, 28496810287352430019813986577684, 347046513903606031118705549409373406

Offset

1,2

Links

R. H. Hardin, Table of n, a(n) for n = 1..17

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....4....4....4....4....4....4....4....4....4
..5....5....5....5....5....5....5....5....5....5....5....5....5....5....5....1
..1....6....6....6....1....6....1....6....6....1....1....1....6....6....6....5
..6....7....3....7....3....7....3....7....7....6....6....6....7....7....7....6
..7....4....2....2....6....4....2....3....3....7....2....7....3....4....4....7
..4....2....5....5....7....2....6....4....2....3....4....3....1....1....2....4
..2....1....7....3....2....5....7....5....6....2....7....4....4....2....1....5
..6....7....6....6....5....1....5....7....5....5....6....5....6....3....7....2
..3....5....1....1....4....6....4....6....1....7....3....7....2....5....3....7
..5....6....4....7....6....7....6....1....4....4....5....2....5....7....6....3
..7....3....7....4....7....3....7....2....7....6....7....6....7....6....5....6

Crossrefs

Sequence in context: A210263 A165067 A236881 * A055153 A190011 A338537

Adjacent sequences: A190926 A190927 A190928 * A190930 A190931 A190932

Keyword

nonn

Author

R. H. Hardin, May 23 2011

Status

approved