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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.

A320514 Numbers k such that sigma(sigma(k)) < 2*k + 1.

Table of values

n a(n)
1 1
2 2
3 4
4 9
5 13
6 16
7 25
8 37
9 43
10 49
11 61
12 64
13 67
14 73
15 81
16 97
17 109
18 121
19 151
20 157
21 163
22 169
23 181
24 193
25 211
26 225
27 229
28 241
29 277
30 283
31 289
32 313
33 331
34 337
35 361
36 373
37 397
38 409
39 421
40 433
41 457
42 487
43 523
44 529
45 541
46 547
47 577
48 601
49 613
50 625
51 631
52 661
53 673
54 691
55 709
56 729
57 733
58 751
59 757
60 787
61 823
62 829
63 841
64 853
65 877

List of values

[1, 2, 4, 9, 13, 16, 25, 37, 43, 49, 61, 64, 67, 73, 81, 97, 109, 121, 151, 157, 163, 169, 181, 193, 211, 225, 229, 241, 277, 283, 289, 313, 331, 337, 361, 373, 397, 409, 421, 433, 457, 487, 523, 529, 541, 547, 577, 601, 613, 625, 631, 661, 673, 691, 709, 729, 733, 751, 757, 787, 823, 829, 841, 853, 877]

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

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