A161119 - cp's OEIS frontend

A161119 Triangle read by rows: T(n,k) is the number of fixed-point-free involutions of {1,2,...,2n} having k cycles with entries of opposite parities (0 <= k <= n).

n	a(n)
0	1
1	0
2	1
3	1
4	0
5	2
6	0
7	9
8	0
9	6
10	9
11	0
12	72
13	0
14	24
15	0
16	225
17	0
18	600
19	0
20	120
21	225
22	0
23	4050
24	0
25	5400
26	0
27	720
28	0
29	11025
30	0
31	66150
32	0
33	52920
34	0
35	5040
36	11025
37	0
38	352800
39	0
40	1058400
41	0
42	564480
43	0
44	40320
45	0
46	893025
47	0
48	9525600
49	0
50	17146080
51	0
52	6531840
53	0
54	362880
55	893025
56	0
57	44651250
58	0
59	238140000
60	0
61	285768000
62	0
63	81648000
64	0
65	3628800

[1, 0, 1, 1, 0, 2, 0, 9, 0, 6, 9, 0, 72, 0, 24, 0, 225, 0, 600, 0, 120, 225, 0, 4050, 0, 5400, 0, 720, 0, 11025, 0, 66150, 0, 52920, 0, 5040, 11025, 0, 352800, 0, 1058400, 0, 564480, 0, 40320, 0, 893025, 0, 9525600, 0, 17146080, 0, 6531840, 0, 362880, 893025, 0, 44651250, 0, 238140000, 0, 285768000, 0, 81648000, 0, 3628800]

cp's OEIS Frontend

A161119 Triangle read by rows: T(n,k) is the number of fixed-point-free involutions of {1,2,...,2n} having k cycles with entries of opposite parities (0 <= k <= n).

Table of values

List of values