A190836 Number of permutations of 7 copies of 1..n introduced in order 1..n with no element equal to another within a distance of 1.

1, 0, 1, 56620, 22875971289, 36533294879349056, 183095824753841610373405, 2421032324142610480402567434373, 74115215422015289392187745053216373265, 4749303210651587675797285013227098386984170468, 588242979144354234332728292738493758656488275002948671

Offset: 0

Author

R. H. Hardin, May 21 2011

Keywords

• nonn

Examples

			Some solutions for n=3
..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....1....3....3....3....3....1....3....3....1....1....1....3....1....3....1
..1....3....1....1....2....2....3....2....2....2....3....2....1....3....2....3
..2....1....2....2....3....3....2....3....1....3....2....1....3....1....3....2
..3....2....3....3....2....1....1....1....3....1....3....3....1....2....1....3
..1....3....2....1....1....3....2....3....1....3....1....1....3....1....2....2
..2....2....1....3....3....1....3....2....2....2....3....2....1....3....3....3
..3....3....2....1....1....2....1....1....3....3....2....3....3....1....2....1
..1....2....3....3....2....1....3....2....2....1....3....1....2....2....1....3
..3....1....1....2....3....3....2....3....3....2....1....2....1....3....3....1
..2....3....2....3....1....1....1....2....2....3....3....1....2....1....1....3
..3....2....3....1....3....3....3....1....3....1....2....3....3....3....2....2
..1....3....2....2....2....2....2....3....1....2....3....2....2....1....1....1
..2....1....3....1....1....3....1....2....3....3....2....3....3....2....3....2
..1....2....2....2....3....2....3....1....1....1....1....1....2....3....1....3
..2....1....1....3....1....3....2....3....3....2....2....3....3....2....2....2
..3....3....3....2....3....2....3....1....1....3....1....2....2....3....3....1
..1....1....1....3....2....1....2....3....2....2....2....3....1....2....1....2
..2....2....3....1....1....2....1....1....1....3....3....2....2....3....3....1
..3....3....1....2....2....1....3....2....2....1....1....3....1....2....2....3
		

Links

• Seiichi Manyama, Table of n, a(n) for n = 0..88 (terms 1..11 from R. J. Mathar)

Crossrefs

Row n=7 of A322013.

Formula

a(n) ~ sqrt(7) * 117649^n * n^(6*n) / (720^n * exp(6*n + 6)). - Vaclav Kotesovec, Nov 24 2018

Extensions

a(0)=1 prepended by Seiichi Manyama, Nov 16 2018