A069721 - cp's OEIS frontend

A069721 Number of rooted unicursal planar maps with n edges and no vertices of valency 1 (unicursal means that exactly two vertices are of odd valency; there is an Eulerian path).

n	a(n)
1	0
2	0
3	4
4	40
5	336
6	2688
7	21120
8	164736
9	1281280
10	9957376
11	77395968
12	601968640
13	4686094336
14	36515020800
15	284817162240
16	2223764766720
17	17379001958400
18	135942415319040
19	1064286014668800
20	8338993950228480
21	65388301768458240
22	513094808135270400
23	4028909667357818880

[0, 0, 4, 40, 336, 2688, 21120, 164736, 1281280, 9957376, 77395968, 601968640, 4686094336, 36515020800, 284817162240, 2223764766720, 17379001958400, 135942415319040, 1064286014668800, 8338993950228480, 65388301768458240, 513094808135270400, 4028909667357818880]

cp's OEIS Frontend

A069721 Number of rooted unicursal planar maps with n edges and no vertices of valency 1 (unicursal means that exactly two vertices are of odd valency; there is an Eulerian path).

Table of values

List of values