A123515 - cp's OEIS frontend

A123515 Triangle read by rows: T(n,k) is the number of involutions of {1,2,...,n} with exactly k fixed points and which contain the pattern 231 exactly once (n>=4, 2<=k<=n-2).

n	a(n)
4	1
5	0
6	2
7	2
8	0
9	3
10	0
11	8
12	0
13	4
14	5
15	0
16	18
17	0
18	5
19	0
20	26
21	0
22	32
23	0
24	6
25	12
26	0
27	75
28	0
29	50
30	0
31	7
32	0
33	76
34	0
35	164
36	0
37	72
38	0
39	8
40	28
41	0
42	264
43	0
44	305
45	0
46	98
47	0
48	9
49	0
50	208
51	0
52	680
53	0
54	510
55	0
56	128
57	0
58	10
59	64
60	0
61	840
62	0
63	1460
64	0
65	791
66	0
67	162
68	0
69	11
70	0
71	544
72	0
73	2480
74	0
75	2772
76	0
77	1160
78	0
79	200
80	0
81	12

[1, 0, 2, 2, 0, 3, 0, 8, 0, 4, 5, 0, 18, 0, 5, 0, 26, 0, 32, 0, 6, 12, 0, 75, 0, 50, 0, 7, 0, 76, 0, 164, 0, 72, 0, 8, 28, 0, 264, 0, 305, 0, 98, 0, 9, 0, 208, 0, 680, 0, 510, 0, 128, 0, 10, 64, 0, 840, 0, 1460, 0, 791, 0, 162, 0, 11, 0, 544, 0, 2480, 0, 2772, 0, 1160, 0, 200, 0, 12]

cp's OEIS Frontend

A123515 Triangle read by rows: T(n,k) is the number of involutions of {1,2,...,n} with exactly k fixed points and which contain the pattern 231 exactly once (n>=4, 2<=k<=n-2).

Table of values

List of values