login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A221145 a(n) is the number of permutations of n elements with exactly one fixed point and no transpositions. 1
1, 0, 0, 8, 30, 144, 1120, 9120, 80892, 808640, 8908416, 106889760, 1389405160, 19452003648, 291782125440, 4668506495744, 79364583206160, 1428562661736960, 27142690917071872, 542853814698737280, 11399930105272855776, 250798462399704792320 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,4

LINKS

Table of n, a(n) for n=1..22.

FORMULA

Equals n*A038205(n-1). - Giovanni Resta, Nov 13 2012

EXAMPLE

For n = 4 the a(4) = 8 solutions are (123), (124), (132), (134), (142), (143), (234), (243)

CROSSREFS

Cf. A038205.

Sequence in context: A161222 A229374 A215471 * A098741 A027146 A302409

Adjacent sequences:  A221142 A221143 A221144 * A221146 A221147 A221148

KEYWORD

nonn

AUTHOR

James Mahoney, Nov 13 2012

EXTENSIONS

Edited by N. J. A. Sloane, Jan 03 2013

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified August 8 12:30 EDT 2022. Contains 356009 sequences. (Running on oeis4.)