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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.

A018806 Sum of gcd(x, y) for 1 <= x, y <= n.

Table of values

n a(n)
1 1
2 5
3 12
4 24
5 37
6 61
7 80
8 112
9 145
10 189
11 220
12 288
13 325
14 389
15 464
16 544
17 593
18 701
19 756
20 880
21 989
22 1093
23 1160
24 1336
25 1441
26 1565
27 1700
28 1880
29 1965
30 2205
31 2296
32 2488
33 2665
34 2829
35 3028
36 3328
37 3437
38 3621
39 3832
40 4152
41 4273
42 4621
43 4748
44 5040
45 5373
46 5597
47 5736
48 6168

List of values

[1, 5, 12, 24, 37, 61, 80, 112, 145, 189, 220, 288, 325, 389, 464, 544, 593, 701, 756, 880, 989, 1093, 1160, 1336, 1441, 1565, 1700, 1880, 1965, 2205, 2296, 2488, 2665, 2829, 3028, 3328, 3437, 3621, 3832, 4152, 4273, 4621, 4748, 5040, 5373, 5597, 5736, 6168]

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

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