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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.

A365445 a(n) is the index of the least prime that is also a centered n-gonal number, or -1 if none exists.

Table of values

n a(n)
3 8
4 3
5 11
6 4
7 14
8 -1
9 -1
10 5
11 19
12 6
13 22
14 14
15 36
16 7
17 27
18 8
19 43
20 18
21 31
22 9
23 34
24 21
25 36
26 22
27 38
28 10
29 795
30 11
31 64
32 25
33 46
34 27
35 47
36 12
37 48
38 50
39 183
40 13
41 394
42 14
43 83
44 121
45 58
46 15
47 61
48 169
49 94
50 36
51 63
52 16
53 489
54 38
55 67
56 68
57 105
58 17
59 623
60 18
61 73
62 74
63 75
64 44
65 347

List of values

[8, 3, 11, 4, 14, -1, -1, 5, 19, 6, 22, 14, 36, 7, 27, 8, 43, 18, 31, 9, 34, 21, 36, 22, 38, 10, 795, 11, 64, 25, 46, 27, 47, 12, 48, 50, 183, 13, 394, 14, 83, 121, 58, 15, 61, 169, 94, 36, 63, 16, 489, 38, 67, 68, 105, 17, 623, 18, 73, 74, 75, 44, 347]

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

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