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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.

A115990 Riordan array (1/sqrt(1-2*x-3*x^2), (1-2*x-3*x^2)/(2*(1-3*x)) - sqrt(1-2*x-3*x^2)/2).

Table of values

n a(n)
0 1
1 1
2 1
3 3
4 2
5 1
6 7
7 5
8 3
9 1
10 19
11 13
12 8
13 4
14 1
15 51
16 35
17 22
18 12
19 5
20 1
21 141
22 96
23 61
24 35
25 17
26 6
27 1
28 393
29 267
30 171
31 101
32 53
33 23
34 7
35 1
36 1107
37 750
38 483
39 291
40 160
41 77
42 30
43 8
44 1
45 3139
46 2123
47 1373
48 839
49 476
50 244
51 108
52 38
53 9
54 1
55 8953
56 6046
57 3923
58 2423
59 1406
60 752
61 360
62 147
63 47
64 10

List of values

[1, 1, 1, 3, 2, 1, 7, 5, 3, 1, 19, 13, 8, 4, 1, 51, 35, 22, 12, 5, 1, 141, 96, 61, 35, 17, 6, 1, 393, 267, 171, 101, 53, 23, 7, 1, 1107, 750, 483, 291, 160, 77, 30, 8, 1, 3139, 2123, 1373, 839, 476, 244, 108, 38, 9, 1, 8953, 6046, 3923, 2423, 1406, 752, 360, 147, 47, 10]

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