A190931 Number of permutations of n copies of 1..7 introduced in order 1..7 with no element equal to another within a distance of 5.

1, 80, 6976, 639552, 60656016, 5898286349, 585487585760, 59147199364720, 6067259409345901, 630842897289489196, 66388460469198215359, 7062901351795999772739, 758832478269321359233282

Offset

1,2

Links

R. H. Hardin, Table of n, a(n) for n = 1..25

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

Crossrefs

Sequence in context: A380975 A259076 A335610 * A006202 A278736 A116252

Adjacent sequences: A190928 A190929 A190930 * A190932 A190933 A190934

Keyword

nonn

Author

R. H. Hardin, May 23 2011

Status

approved