A161126 - cp's OEIS frontend

A161126 Triangle read by rows: T(n,k) is the number of involutions of {1,2,...,n} having k descents (n >= 1; 0 <= k < n).

n	a(n)
1	1
2	1
3	1
4	1
5	2
6	1
7	1
8	4
9	4
10	1
11	1
12	6
13	12
14	6
15	1
16	1
17	9
18	28
19	28
20	9
21	1
22	1
23	12
24	57
25	92
26	57
27	12
28	1
29	1
30	16
31	105
32	260
33	260
34	105
35	16
36	1
37	1
38	20
39	179
40	630
41	960
42	630
43	179
44	20
45	1
46	1
47	25
48	289
49	1397
50	3036
51	3036
52	1397
53	289
54	25
55	1
56	1
57	30
58	444
59	2836
60	8471
61	12132
62	8471
63	2836
64	444
65	30
66	1
67	1
68	36

[1, 1, 1, 1, 2, 1, 1, 4, 4, 1, 1, 6, 12, 6, 1, 1, 9, 28, 28, 9, 1, 1, 12, 57, 92, 57, 12, 1, 1, 16, 105, 260, 260, 105, 16, 1, 1, 20, 179, 630, 960, 630, 179, 20, 1, 1, 25, 289, 1397, 3036, 3036, 1397, 289, 25, 1, 1, 30, 444, 2836, 8471, 12132, 8471, 2836, 444, 30, 1, 1, 36]

cp's OEIS Frontend

A161126 Triangle read by rows: T(n,k) is the number of involutions of {1,2,...,n} having k descents (n >= 1; 0 <= k < n).

Table of values

List of values