A178881 - cp's OEIS frontend

A178881 Sum of all pairs of greatest common divisors for (i,j) where 1 <= i < j <= n.

n	a(n)
1	0
2	1
3	3
4	7
5	11
6	20
7	26
8	38
9	50
10	67
11	77
12	105
13	117
14	142
15	172
16	204
17	220
18	265
19	283
20	335
21	379
22	420
23	442
24	518
25	558
26	607
27	661
28	737
29	765
30	870
31	900
32	980
33	1052
34	1117
35	1199
36	1331
37	1367
38	1440
39	1526
40	1666
41	1706
42	1859
43	1901
44	2025
45	2169
46	2258
47	2304
48	2496
49	2580
50	2725

[0, 1, 3, 7, 11, 20, 26, 38, 50, 67, 77, 105, 117, 142, 172, 204, 220, 265, 283, 335, 379, 420, 442, 518, 558, 607, 661, 737, 765, 870, 900, 980, 1052, 1117, 1199, 1331, 1367, 1440, 1526, 1666, 1706, 1859, 1901, 2025, 2169, 2258, 2304, 2496, 2580, 2725]

cp's OEIS Frontend

A178881 Sum of all pairs of greatest common divisors for (i,j) where 1 <= i < j <= n.

Table of values

List of values