A178515 - cp's OEIS frontend

A178515 Triangle read by rows: T(n,k) is the number of involutions of {1,2,...,n} having genus k (see first comment for definition of genus).

n	a(n)
1	1
2	2
3	0
4	4
5	0
6	0
7	9
8	1
9	0
10	0
11	21
12	5
13	0
14	0
15	0
16	51
17	25
18	0
19	0
20	0
21	0
22	127
23	105
24	0
25	0
26	0
27	0
28	0
29	323
30	420
31	21
32	0
33	0
34	0
35	0
36	0
37	835
38	1596
39	189
40	0
41	0
42	0
43	0
44	0
45	0
46	2188
47	5880
48	1428
49	0
50	0
51	0
52	0
53	0
54	0
55	0
56	5798
57	21120
58	8778
59	0
60	0
61	0
62	0
63	0
64	0
65	0
66	0
67	15511
68	74415
69	48741
70	1485
71	0
72	0
73	0
74	0
75	0
76	0
77	0
78	0
79	41835
80	258115
81	249249
82	19305
83	0

[1, 2, 0, 4, 0, 0, 9, 1, 0, 0, 21, 5, 0, 0, 0, 51, 25, 0, 0, 0, 0, 127, 105, 0, 0, 0, 0, 0, 323, 420, 21, 0, 0, 0, 0, 0, 835, 1596, 189, 0, 0, 0, 0, 0, 0, 2188, 5880, 1428, 0, 0, 0, 0, 0, 0, 0, 5798, 21120, 8778, 0, 0, 0, 0, 0, 0, 0, 0, 15511, 74415, 48741, 1485, 0, 0, 0, 0, 0, 0, 0, 0, 41835, 258115, 249249, 19305, 0]

cp's OEIS Frontend

A178515 Triangle read by rows: T(n,k) is the number of involutions of {1,2,...,n} having genus k (see first comment for definition of genus).

Table of values

List of values