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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.

A155025 Primes p=A000040(n) with nonprime index n such that the concatenation n//p is a composite number.

Table of values

n a(n)
1 2
2 19
3 23
4 29
5 43
6 47
7 53
8 71
9 73
10 79
11 89
12 97
13 101
14 107
15 131
16 137
17 139
18 163
19 167
20 173
21 193
22 223
23 227
24 229
25 233
26 239
27 257
28 281
29 293
30 307
31 311
32 313
33 317
34 337
35 347
36 349
37 359
38 373
39 379
40 383
41 389
42 397
43 409
44 419
45 433
46 443
47 449
48 457
49 463
50 467
51 491
52 499
53 503
54 521
55 541
56 557
57 569

List of values

[2, 19, 23, 29, 43, 47, 53, 71, 73, 79, 89, 97, 101, 107, 131, 137, 139, 163, 167, 173, 193, 223, 227, 229, 233, 239, 257, 281, 293, 307, 311, 313, 317, 337, 347, 349, 359, 373, 379, 383, 389, 397, 409, 419, 433, 443, 449, 457, 463, 467, 491, 499, 503, 521, 541, 557, 569]

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

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