login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A332651 Number of polygonal cacti on n unlabeled nodes with every polygon having an even number of edges. 3
1, 1, 0, 0, 1, 0, 1, 1, 1, 1, 4, 2, 7, 9, 14, 26, 48, 71, 154, 243, 478, 894, 1631, 3149, 6062, 11295, 22469, 42900, 83528, 164829, 321012, 632960, 1255613, 2472803, 4928140, 9808439, 19533534, 39134059, 78345317, 157177556, 316398963, 636790282, 1284910954 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,11

COMMENTS

Bridges are disallowed.

LINKS

Andrew Howroyd, Table of n, a(n) for n = 0..200

Wikipedia, Cactus graph

Index entries for sequences related to cacti

EXAMPLE

a(6) = 1 corresponding with a hexagon.

a(7) = 1 corresponding with two quadrilaterals joined at a node.

PROG

(PARI) \\ See A332650 for UCacti.

seq(n)={concat([1], UCacti(vector(n, i, i>2&&i%2==0)))}

CROSSREFS

Cf. A000083, A035085, A091487, A332649, A332650.

Sequence in context: A203575 A120871 A019689 * A072009 A257502 A201207

Adjacent sequences:  A332648 A332649 A332650 * A332652 A332653 A332654

KEYWORD

nonn

AUTHOR

Andrew Howroyd, Feb 18 2020

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 April 11 22:01 EDT 2021. Contains 342888 sequences. (Running on oeis4.)