A092580 - cp's OEIS frontend

A092580 Triangle read by rows: T(n,k) is the number of permutations p of [n] in which exactly the first k terms satisfy the up-down property, i.e., p(1) p(2)>p(3), p(3) ...

n	a(n)
1	1
2	1
3	1
4	3
5	1
6	2
7	12
8	4
9	3
10	5
11	60
12	20
13	15
14	9
15	16
16	360
17	120
18	90
19	54
20	35
21	61
22	2520
23	840
24	630
25	378
26	245
27	155
28	272
29	20160
30	6720
31	5040
32	3024
33	1960
34	1240
35	791
36	1385
37	181440
38	60480
39	45360
40	27216
41	17640
42	11160
43	7119
44	4529
45	7936
46	1814400
47	604800
48	453600
49	272160
50	176400
51	111600
52	71190
53	45290
54	28839
55	50521

[1, 1, 1, 3, 1, 2, 12, 4, 3, 5, 60, 20, 15, 9, 16, 360, 120, 90, 54, 35, 61, 2520, 840, 630, 378, 245, 155, 272, 20160, 6720, 5040, 3024, 1960, 1240, 791, 1385, 181440, 60480, 45360, 27216, 17640, 11160, 7119, 4529, 7936, 1814400, 604800, 453600, 272160, 176400, 111600, 71190, 45290, 28839, 50521]

cp's OEIS Frontend

A092580 Triangle read by rows: T(n,k) is the number of permutations p of [n] in which exactly the first k terms satisfy the up-down property, i.e., p(1) p(2)>p(3), p(3) ...

Table of values

List of values