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!)
A261479 Number of set partitions of [2n] into exactly n parts such that no part contains two elements with a circular distance less than three. 2
1, 0, 0, 1, 7, 458, 18944, 858023, 42615547, 2331292564, 140077132527, 9199520194445, 656844469384222, 50720708063406821, 4215138323234299756, 375319710150454887887, 35660986210126871452435, 3602425696957042245685448, 385625195068544676072425069 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,5
COMMENTS
The circular distance of 1 and n is 1 (for n>1).
LINKS
FORMULA
a(n) = A261477(2n,n).
EXAMPLE
a(0) = 1: {}.
a(3) = 1: 14|25|36.
a(4) = 7: 14|26|37|58, 14|27|36|58, 15|26|37|48, 15|26|38|47, 15|27|36|48, 16|25|37|48, 16|25|38|47.
a(5) = 458: 147|258|3,10|6|9, 147|258|36|9|10, 147|258|39|6|10, ..., 1|29|36,10|47|58, 1|29|36|47,10|58, 1|2|369|47,10|58.
CROSSREFS
Cf. A261477.
Sequence in context: A009660 A024097 A203060 * A241363 A196540 A215890
KEYWORD
nonn
AUTHOR
Alois P. Heinz, Aug 20 2015
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 February 29 19:20 EST 2024. Contains 370428 sequences. (Running on oeis4.)