A330320 - cp's OEIS frontend

A330320 a(n) = Sum_{i=1..n} tau(i)*tau(i+1), where tau(n) = A000005(n) is the number of divisors of n.

n	a(n)
1	2
2	6
3	12
4	18
5	26
6	34
7	42
8	54
9	66
10	74
11	86
12	98
13	106
14	122
15	142
16	152
17	164
18	176
19	188
20	212
21	228
22	236
23	252
24	276
25	288
26	304
27	328
28	340
29	356
30	372
31	384
32	408
33	424
34	440
35	476
36	494
37	502
38	518
39	550
40	566
41	582
42	598
43	610
44	646
45	670
46	678
47	698
48	728
49	746
50	770
51	794
52	806
53	822
54	854
55	886
56	918
57	934
58	942
59	966
60	990
61	998
62	1022
63	1064
64	1092
65	1124
66	1140

[2, 6, 12, 18, 26, 34, 42, 54, 66, 74, 86, 98, 106, 122, 142, 152, 164, 176, 188, 212, 228, 236, 252, 276, 288, 304, 328, 340, 356, 372, 384, 408, 424, 440, 476, 494, 502, 518, 550, 566, 582, 598, 610, 646, 670, 678, 698, 728, 746, 770, 794, 806, 822, 854, 886, 918, 934, 942, 966, 990, 998, 1022, 1064, 1092, 1124, 1140]

cp's OEIS Frontend

A330320 a(n) = Sum_{i=1..n} tau(i)*tau(i+1), where tau(n) = A000005(n) is the number of divisors of n.

Table of values

List of values