The On-Line Encyclopedia of Integer Sequences (OEIS)

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A177294

Number of permutations of 3 copies of 1..n with all adjacent differences <= 4 in absolute value.
(history; published version)

#6 by Alois P. Heinz at Mon Jan 18 18:32:37 EST 2016

STATUS

editing

approved

#5 by Alois P. Heinz at Mon Jan 18 18:32:30 EST 2016

DATA

1, 1, 20, 1680, 369600, 168168000, 41494252800, 6923871998400, 983114244363720, 139528504017728552

OFFSET

1,2

0,3

#4 by Alois P. Heinz at Mon Jan 18 16:36:58 EST 2016

COMMENTS

a(n) = (3n)!/6^n for n<=5.

CROSSREFS

Cf. A014606.

AUTHOR

R. H. Hardin , May 06 2010

STATUS

approved

editing

#3 by Russ Cox at Sat Mar 31 12:35:42 EDT 2012

AUTHOR

_R. H. Hardin (rhhardin(AT)att.net) _ May 06 2010

Discussion

Sat Mar 31

12:35

OEIS Server: https://oeis.org/edit/global/875

#2 by N. J. A. Sloane at Sat Oct 02 03:00:00 EDT 2010

KEYWORD

nonn,new

nonn

AUTHOR

Ron R. H. Hardin (rhhardin(AT)att.net) May 06 2010

#1 by N. J. A. Sloane at Tue Jun 01 03:00:00 EDT 2010

NAME

Number of permutations of 3 copies of 1..n with all adjacent differences <= 4 in absolute value.

DATA

1, 20, 1680, 369600, 168168000, 41494252800, 6923871998400, 983114244363720, 139528504017728552

OFFSET

1,2

COMMENTS

a(n)=(3n)!/6^n for n<=5

KEYWORD

nonn,new

AUTHOR

Ron Hardin (rhhardin(AT)att.net) May 06 2010

STATUS

approved