A068991 - cp's OEIS frontend

A068991 Numbers k such that Sum_{d divides k} sigma(d)/phi(d) is an integer.

n	a(n)
1	1
2	2
3	3
4	6
5	10
6	21
7	30
8	42
9	78
10	110
11	210
12	330
13	390
14	930
15	1218
16	1830
17	2025
18	2310
19	2530
20	4050
21	4134
22	4290
23	6090
24	7590
25	14175
26	14910
27	22110
28	28350
29	51090
30	52650
31	53130
32	66990
33	71862
34	98670
35	118910
36	159975
37	214650
38	319950
39	356730
40	359310
41	442338
42	635850
43	684450

[1, 2, 3, 6, 10, 21, 30, 42, 78, 110, 210, 330, 390, 930, 1218, 1830, 2025, 2310, 2530, 4050, 4134, 4290, 6090, 7590, 14175, 14910, 22110, 28350, 51090, 52650, 53130, 66990, 71862, 98670, 118910, 159975, 214650, 319950, 356730, 359310, 442338, 635850, 684450]

cp's OEIS Frontend

A068991 Numbers k such that Sum_{d divides k} sigma(d)/phi(d) is an integer.

Table of values

List of values