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!)
A134799 a(n)=3^((3^n - 1)/2). 0
1, 3, 81, 1594323, 12157665459056928801 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

Number of partitions into "bus routes" of the graph G_{n+1} defined below.

LINKS

Table of n, a(n) for n=0..4.

Author?, Mitsumata tree

EXAMPLE

.........|..................G_1

****

.......__|__................G_2

.........|

****

.__|_____|_____|__..........G_3

...|.....|.....|

.........|

.......__|__

.........|

****.

..._|_........._|_..........G_4

_|__|_____|_____|__|_

.|._|_....|...._|_.|

....|.....|.....|

......_|__|__|_

.......|._|_.|

..........|

****

G_1 = o---. = rooted tree with one edge and one leaf node. For n > 0, G_{n+1} is obtained from G_n by splitting each leaf node into three.

CROSSREFS

Cf. A131709

Sequence in context: A060722 A183502 A325053 * A055590 A037111 A067202

Adjacent sequences:  A134796 A134797 A134798 * A134800 A134801 A134802

KEYWORD

nonn,easy

AUTHOR

Yasutoshi Kohmoto, Jan 09 2008

EXTENSIONS

Edited by N. J. A. Sloane, Jan 29 2008

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 May 26 13:17 EDT 2022. Contains 354092 sequences. (Running on oeis4.)