|
| |
|
|
A103944
|
|
Number of rooted unicursal n-edge maps in the plane (planar with a distinguished outside face).
|
|
1
| |
|
|
1, 10, 93, 836, 7355, 63750, 546553, 4646920, 39250935, 329789450, 2758868981, 22995369996, 191074697203, 1583463268366, 13092015636465, 108024564809744, 889730213085167, 7316434446188562, 60078376613838829, 492692533579612180
(list; graph; refs; listen; history; internal format)
|
|
|
|
OFFSET
| 1,2
|
|
|
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
| 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*binomial(2n, n)sum_{i=0..n-2} binomial(n-2, i)(1/(n+1+i)+n/(n+2+i)).
|
|
|
CROSSREFS
| Cf. A069720, A103945.
Sequence in context: A037534 A120996 A190990 * A190989 A099295 A167589
Adjacent sequences: A103941 A103942 A103943 * A103945 A103946 A103947
|
|
|
KEYWORD
| easy,nonn
|
|
|
AUTHOR
| Valery A. Liskovets (liskov(AT)im.bas-net.by), Mar 17 2005
|
| |
|
|
