A161664 - cp's OEIS frontend

A161664 a(n) = Sum_{i=1..n} (i - d(i)), where d(n) is the number of divisors of n (A000005).

n	a(n)
1	0
2	0
3	1
4	2
5	5
6	7
7	12
8	16
9	22
10	28
11	37
12	43
13	54
14	64
15	75
16	86
17	101
18	113
19	130
20	144
21	161
22	179
23	200
24	216
25	238
26	260
27	283
28	305
29	332
30	354
31	383
32	409
33	438
34	468
35	499
36	526
37	561
38	595
39	630
40	662
41	701
42	735
43	776
44	814
45	853
46	895
47	940
48	978
49	1024
50	1068
51	1115
52	1161
53	1212
54	1258
55	1309

[0, 0, 1, 2, 5, 7, 12, 16, 22, 28, 37, 43, 54, 64, 75, 86, 101, 113, 130, 144, 161, 179, 200, 216, 238, 260, 283, 305, 332, 354, 383, 409, 438, 468, 499, 526, 561, 595, 630, 662, 701, 735, 776, 814, 853, 895, 940, 978, 1024, 1068, 1115, 1161, 1212, 1258, 1309]

cp's OEIS Frontend

A161664 a(n) = Sum_{i=1..n} (i - d(i)), where d(n) is the number of divisors of n (A000005).

Table of values

List of values