login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A007973 Number of permutations that are n-2 "block reversals" away from 12...n. 4
1, 3, 15, 55, 184, 648, 2111, 6352, 17337, 42878 (list; graph; refs; listen; history; text; internal format)
OFFSET

2,2

LINKS

Table of n, a(n) for n=2..11.

FORMULA

a(n) = A300003(n,n-2).

CROSSREFS

Cf. A007972, A007974, A007975, A300003.

Sequence in context: A119113 A286185 A152896 * A261737 A015249 A084152

Adjacent sequences:  A007970 A007971 A007972 * A007974 A007975 A007976

KEYWORD

nonn,more

AUTHOR

J. H. Conway

EXTENSIONS

a(9)-a(11) from Sean A. Irvine, Feb 22 2018

STATUS

approved

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

License Agreements, Terms of Use, Privacy Policy .

Last modified May 24 04:23 EDT 2018. Contains 304500 sequences. (Running on oeis4.)