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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.

A060351 If the binary expansion of n has k bits, let S be the subset of [k-1] such that i is in S if the i-th bit of n is a 1 (with the first bit being the least significant bit); a(n) is the number of permutations of [k] with descent set S.

Table of values

n a(n)
0 1
1 1
2 1
3 1
4 1
5 2
6 2
7 1
8 1
9 3
10 5
11 3
12 3
13 5
14 3
15 1
16 1
17 4
18 9
19 6
20 9
21 16
22 11
23 4
24 4
25 11
26 16
27 9
28 6
29 9
30 4
31 1
32 1
33 5
34 14
35 10
36 19
37 35
38 26
39 10
40 14
41 40
42 61
43 35
44 26
45 40
46 19
47 5
48 5
49 19
50 40
51 26
52 35
53 61
54 40
55 14
56 10
57 26
58 35
59 19
60 10
61 14
62 5
63 1
64 1

List of values

[1, 1, 1, 1, 1, 2, 2, 1, 1, 3, 5, 3, 3, 5, 3, 1, 1, 4, 9, 6, 9, 16, 11, 4, 4, 11, 16, 9, 6, 9, 4, 1, 1, 5, 14, 10, 19, 35, 26, 10, 14, 40, 61, 35, 26, 40, 19, 5, 5, 19, 40, 26, 35, 61, 40, 14, 10, 26, 35, 19, 10, 14, 5, 1, 1]

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