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.

A128060 a(n) = 2*n - numerator((2*n-1)^2/(2*(2*n)!)).

Table of values

n a(n)
0 -1
1 1
2 1
3 1
4 1
5 9
6 1
7 1
8 15
9 1
10 1
11 21
12 1
13 25
14 27
15 1
16 1
17 33
18 35
19 1
20 39
21 1
22 1
23 45
24 1
25 49
26 51
27 1
28 55
29 57
30 1
31 1
32 63
33 65
34 1
35 69
36 1
37 1
38 75
39 77
40 1
41 81
42 1
43 85
44 87
45 1
46 91
47 93
48 95
49 1
50 99
51 1
52 1
53 105
54 1
55 1
56 111
57 1
58 115
59 117
60 119
61 121
62 123
63 125
64 1
65 129
66 1
67 133
68 135
69 1
70 1
71 141
72 143
73 145
74 147

List of values

[-1, 1, 1, 1, 1, 9, 1, 1, 15, 1, 1, 21, 1, 25, 27, 1, 1, 33, 35, 1, 39, 1, 1, 45, 1, 49, 51, 1, 55, 57, 1, 1, 63, 65, 1, 69, 1, 1, 75, 77, 1, 81, 1, 85, 87, 1, 91, 93, 95, 1, 99, 1, 1, 105, 1, 1, 111, 1, 115, 117, 119, 121, 123, 125, 1, 129, 1, 133, 135, 1, 1, 141, 143, 145, 147]