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

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A304983 Number of unlabeled clutters (connected antichains) spanning n vertices with singleton edges allowed. 8
1, 1, 3, 14, 118, 2916, 819473 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

LINKS

Table of n, a(n) for n=0..6.

FORMULA

Inverse Euler transform of A304997. - Andrew Howroyd, Aug 14 2019

EXAMPLE

Non-isomorphic representatives of the a(3) = 14 clutters:

  {{1,2,3}}

  {{1,3},{2,3}}

  {{3},{1,2,3}}

  {{1,2},{1,3},{2,3}}

  {{3},{1,2},{2,3}}

  {{3},{1,3},{2,3}}

  {{2},{3},{1,2,3}}

  {{1},{2},{3},{1,2,3}}

  {{2},{3},{1,2},{1,3}}

  {{3},{1,2},{1,3},{2,3}}

  {{2},{3},{1,3},{2,3}}

  {{1},{2},{3},{1,3},{2,3}}

  {{2},{3},{1,2},{1,3},{2,3}}

  {{1},{2},{3},{1,2},{1,3},{2,3}}

CROSSREFS

Cf. A048143, A198085, A261006, A304912, A304981, A304982, A304983, A304984, A304985, A304986, A304997.

Sequence in context: A122081 A007140 A161936 * A260887 A127850 A324147

Adjacent sequences:  A304980 A304981 A304982 * A304984 A304985 A304986

KEYWORD

nonn,more

AUTHOR

Gus Wiseman, May 23 2018

EXTENSIONS

a(5)-a(6) from Andrew Howroyd, Aug 14 2019

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
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified September 20 08:08 EDT 2019. Contains 327214 sequences. (Running on oeis4.)