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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.

A345230 a(n) = Sum_{1 <= x_1 <= x_2 <= ... <= x_n <= n} gcd(x_1, x_2, ..., x_n).

Table of values

n a(n)
0 0
1 1
2 4
3 13
4 44
5 140
6 512
7 1782
8 6652
9 24682
10 93599
11 354341
12 1359470
13 5210328
14 20098886
15 77621774
16 300797854
17 1167164438
18 4539201401
19 17674941735
20 68933414989
21 269143872226
22 1052114789548
23 4116808923486
24 16124224585644
25 63205911146740
26 247961982954952

List of values

[0, 1, 4, 13, 44, 140, 512, 1782, 6652, 24682, 93599, 354341, 1359470, 5210328, 20098886, 77621774, 300797854, 1167164438, 4539201401, 17674941735, 68933414989, 269143872226, 1052114789548, 4116808923486, 16124224585644, 63205911146740, 247961982954952]

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

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