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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.

A263931 a(n) = binomial(2*n, n) / Product(p prime | n < p <= 2*n).

Table of values

n a(n)
0 1
1 1
2 2
3 4
4 2
5 36
6 12
7 24
8 90
9 20
10 4
11 168
12 28
13 1400
14 5400
15 720
16 90
17 5940
18 23100
19 46200
20 180180
21 17160
22 1560
23 140400
24 11700
25 45864
26 179928
27 13328
28 52360
29 5969040
30 397936
31 795872
32 3133746
33 12345060
34 726180
35 2863224
36 159068
37 318136
38 1255800
39 4958800
40 247940

List of values

[1, 1, 2, 4, 2, 36, 12, 24, 90, 20, 4, 168, 28, 1400, 5400, 720, 90, 5940, 23100, 46200, 180180, 17160, 1560, 140400, 11700, 45864, 179928, 13328, 52360, 5969040, 397936, 795872, 3133746, 12345060, 726180, 2863224, 159068, 318136, 1255800, 4958800, 247940]

Started in 1964 by Neil J. A. Sloane | Maintained by The OEIS Foundation Inc.

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