A123513 - cp's OEIS frontend

A123513 Triangle read by rows: T(n,k) is the number of permutations of [n] having k small descents (n >= 1; 0 <= k <= n-1). A small descent in a permutation (x_1,x_2,...,x_n) is a position i such that x_i - x_(i+1) = 1.

n	a(n)
1	1
2	1
3	1
4	3
5	2
6	1
7	11
8	9
9	3
10	1
11	53
12	44
13	18
14	4
15	1
16	309
17	265
18	110
19	30
20	5
21	1
22	2119
23	1854
24	795
25	220
26	45
27	6
28	1
29	16687
30	14833
31	6489
32	1855
33	385
34	63
35	7
36	1
37	148329
38	133496
39	59332
40	17304
41	3710
42	616
43	84
44	8
45	1
46	1468457
47	1334961
48	600732
49	177996
50	38934
51	6678
52	924
53	108
54	9
55	1

[1, 1, 1, 3, 2, 1, 11, 9, 3, 1, 53, 44, 18, 4, 1, 309, 265, 110, 30, 5, 1, 2119, 1854, 795, 220, 45, 6, 1, 16687, 14833, 6489, 1855, 385, 63, 7, 1, 148329, 133496, 59332, 17304, 3710, 616, 84, 8, 1, 1468457, 1334961, 600732, 177996, 38934, 6678, 924, 108, 9, 1]

cp's OEIS Frontend

A123513 Triangle read by rows: T(n,k) is the number of permutations of [n] having k small descents (n >= 1; 0 <= k <= n-1). A small descent in a permutation (x_1,x_2,...,x_n) is a position i such that x_i - x_(i+1) = 1.

Table of values

List of values