A190930 Number of permutations of n copies of 1..7 introduced in order 1..7 with no element equal to another within a distance of 4

1, 876, 930776, 1121366420, 1480802920785, 2096040262602013, 3130500265589863279, 4877720372114515794195, 7863552772351099534263185, 13036319691799230161857187106, 22121167328810053450410257014723

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

Crossrefs

Sequence in context: A297511 A297725 A185989 * A209743 A346900 A346884

Adjacent sequences: A190927 A190928 A190929 * A190931 A190932 A190933

Keyword

nonn

Author

R. H. Hardin May 23 2011

Status

approved