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

 

Logo

Annual Appeal: Today, Nov 11 2014, is the 4th anniversary of the launch of the new OEIS web site. 70,000 sequences have been added in these four years, all edited by volunteers. Please make a donation (tax deductible in the US) to help keep the OEIS running.

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A103938 Number of rooted non-separable n-edge maps in the plane (planar with a distinguished outside face). 1
3, 2, 5, 18, 77, 364, 1836, 9690, 52877, 296010, 1690845, 9817080, 57769740, 343806368, 2065802056, 12515350122, 76367432013, 468922828150, 2895381678735, 17966214519330 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

REFERENCES

V. A. Liskovets and T. R. Walsh, Enumeration of unrooted maps on the plane, Rapport technique, UQAM, No. 2005-01, Montreal, Canada, 2005.

LINKS

Table of n, a(n) for n=1..20.

V. A. Liskovets and T. R. Walsh, Counting unrooted maps on the plane, Advances in Applied Math., 36, No.4 (2006), 364-387.

FORMULA

a(n)=(n+2)*A000139(n)/2.

CROSSREFS

Sequence in context: A187943 A214502 A077039 * A085973 A248243 A005265

Adjacent sequences:  A103935 A103936 A103937 * A103939 A103940 A103941

KEYWORD

easy,nonn

AUTHOR

Valery A. Liskovets, Mar 17 2005

STATUS

approved

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

Content is available under The OEIS End-User License Agreement .

Last modified December 18 06:09 EST 2014. Contains 252079 sequences.