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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.

A068978 Numbers k such that Sum_{d|k} tau(d)/d is an integer, where tau(x) = A000005(x).

Table of values

n a(n)
1 1
2 2
3 9
4 18
5 105
6 210
7 24375
8 48750
9 133848
10 18780741
11 18780965
12 37561482
13 37561930
14 121486365
15 169028685
16 242972730
17 338057370
18 360988056
19 676114740
20 1120584213
21 1285201500
22 1352229480
23 2241168426
24 2776831200
25 5352575025
26 5408917920
27 7437262140
28 10705150050

List of values

[1, 2, 9, 18, 105, 210, 24375, 48750, 133848, 18780741, 18780965, 37561482, 37561930, 121486365, 169028685, 242972730, 338057370, 360988056, 676114740, 1120584213, 1285201500, 1352229480, 2241168426, 2776831200, 5352575025, 5408917920, 7437262140, 10705150050]

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

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