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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.

A054987 Smallest composite x such that sigma(x+2^n) = sigma(x) + 2^n.

Table of values

n a(n)
1 434
2 305635357
3 27
4 39
5 106645
6 69
7 2275
8 63
9 6475
10 249
11 7735
12 3703
13 10803
14 16383
15 58869
16 51181
17 87951
18 1695
19 9579
20 105237
21 98829
22 1143369
23 789609
24 11625
25 14038691
26 178975
27 48627929
28 1881333
29 402373721
30 2667945
31 82915599
32 353195221
33 70106601

List of values

[434, 305635357, 27, 39, 106645, 69, 2275, 63, 6475, 249, 7735, 3703, 10803, 16383, 58869, 51181, 87951, 1695, 9579, 105237, 98829, 1143369, 789609, 11625, 14038691, 178975, 48627929, 1881333, 402373721, 2667945, 82915599, 353195221, 70106601]

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

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