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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.

A343518 a(n) = Sum_{1 <= x_1 <= x_2 <= x_3 <= x_4 <= n} gcd(x_1, x_2, x_3 , x_4, n).

Table of values

n a(n)
1 1
2 6
3 17
4 42
5 74
6 153
7 216
8 379
9 531
10 809
11 1011
12 1605
13 1832
14 2626
15 3268
16 4304
17 4861
18 6798
19 7333
20 9878
21 11148
22 13711
23 14972
24 19985
25 20775
26 25643
27 28503
28 34517
29 35988
30 46162
31 46406
32 57092
33 61077
34 70986
35 75099
36 92520
37 91426
38 108693
39 115774
40 135491
41 135791
42 165719
43 163227
44 193437

List of values

[1, 6, 17, 42, 74, 153, 216, 379, 531, 809, 1011, 1605, 1832, 2626, 3268, 4304, 4861, 6798, 7333, 9878, 11148, 13711, 14972, 19985, 20775, 25643, 28503, 34517, 35988, 46162, 46406, 57092, 61077, 70986, 75099, 92520, 91426, 108693, 115774, 135491, 135791, 165719, 163227, 193437]

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

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