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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.

A189175 Riordan matrix (1+x/sqrt(1-4*x),(1-sqrt(1-4*x))/2).

Table of values

n a(n)
0 1
1 1
2 1
3 2
4 2
5 1
6 6
7 5
8 3
9 1
10 20
11 15
12 9
13 4
14 1
15 70
16 49
17 29
18 14
19 5
20 1
21 252
22 168
23 98
24 49
25 20
26 6
27 1
28 924
29 594
30 342
31 174
32 76
33 27
34 7
35 1
36 3432
37 2145
38 1221
39 627
40 285
41 111
42 35
43 8
44 1
45 12870
46 7865
47 4433
48 2288
49 1067
50 440
51 155
52 44
53 9
54 1
55 48620
56 29172
57 16302
58 8437
59 4004
60 1716
61 649
62 209
63 54
64 10
65 1

List of values

[1, 1, 1, 2, 2, 1, 6, 5, 3, 1, 20, 15, 9, 4, 1, 70, 49, 29, 14, 5, 1, 252, 168, 98, 49, 20, 6, 1, 924, 594, 342, 174, 76, 27, 7, 1, 3432, 2145, 1221, 627, 285, 111, 35, 8, 1, 12870, 7865, 4433, 2288, 1067, 440, 155, 44, 9, 1, 48620, 29172, 16302, 8437, 4004, 1716, 649, 209, 54, 10, 1]

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

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