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A190831 Number of permutations of 4 copies of 1..n introduced in order 1..n with no element equal to another within a distance of 2 0
0, 0, 1, 1277, 1903102, 4336589521, 14956351701700, 75493034668888898 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,4

LINKS

Table of n, a(n) for n=1..8.

EXAMPLE

Some solutions for n=4

..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....1....1....4....4....4....4....4....4....1....4....4

..1....1....1....2....2....4....4....1....2....1....1....2....2....4....2....2

..2....3....2....3....1....2....2....2....3....3....3....1....3....3....1....1

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

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

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

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

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

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

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

..4....4....1....3....4....3....1....3....1....4....4....4....1....3....4....1

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

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

CROSSREFS

Sequence in context: A282440 A211685 A210365 * A202643 A237407 A251097

Adjacent sequences:  A190828 A190829 A190830 * A190832 A190833 A190834

KEYWORD

nonn

AUTHOR

R. H. Hardin May 21 2011

STATUS

approved

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Last modified September 23 20:42 EDT 2021. Contains 347617 sequences. (Running on oeis4.)