cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A186363 Triangle read by rows: T(n,k) is the number of cycle-up-down permutations of {1,2,...,n} having k fixed points (0 <= k <= n). A permutation is said to be cycle-up-down if it is a product of up-down cycles. A cycle (b(1), b(2), ...) is said to be up-down if, when written with its smallest element in the first position, it satisfies b(1) < b(2) > b(3) < ... .

Table of values

n a(n)
0 1
1 0
2 1
3 1
4 0
5 1
6 1
7 3
8 0
9 1
10 5
11 4
12 6
13 0
14 1
15 15
16 25
17 10
18 10
19 0
20 1
21 71
22 90
23 75
24 20
25 15
26 0
27 1
28 341
29 497
30 315
31 175
32 35
33 21
34 0
35 1
36 1945
37 2728
38 1988
39 840
40 350
41 56
42 28
43 0
44 1
45 12135
46 17505
47 12276
48 5964
49 1890
50 630
51 84
52 36
53 0
54 1
55 84091
56 121350
57 87525
58 40920
59 14910
60 3780
61 1050
62 120
63 45
64 0
65 1

List of values

[1, 0, 1, 1, 0, 1, 1, 3, 0, 1, 5, 4, 6, 0, 1, 15, 25, 10, 10, 0, 1, 71, 90, 75, 20, 15, 0, 1, 341, 497, 315, 175, 35, 21, 0, 1, 1945, 2728, 1988, 840, 350, 56, 28, 0, 1, 12135, 17505, 12276, 5964, 1890, 630, 84, 36, 0, 1, 84091, 121350, 87525, 40920, 14910, 3780, 1050, 120, 45, 0, 1]