A286842 - cp's OEIS frontend

A286842 Least k such that the sum of proper divisors of k*n is a prime number, or -1 if no such k exists.

n	a(n)
1	4
2	2
3	7
4	1
5	7
6	54
7	3
8	1
9	3
10	5
11	5
12	27
13	3
14	7
15	35
16	2
17	5
18	18
19	3
20	40
21	1
22	11
23	5
24	96
25	2
26	13
27	1
28	14
29	7
30	120
31	5
32	1
33	99
34	68
35	1
36	9
37	3
38	19
39	1
40	20
41	5
42	5145000
43	3
44	88
45	80
46	23
47	5
48	48
49	2
50	1
51	323
52	52
53	5
54	6
55	1
56	7
57	1
58	116
59	7
60	60
61	5
62	124
63	1
64	2
65	1
66	1650
67	3
68	34
69	299
70	35
71	7
72	32
73	5
74	37
75	7
76	19
77	1
78	26693550

[4, 2, 7, 1, 7, 54, 3, 1, 3, 5, 5, 27, 3, 7, 35, 2, 5, 18, 3, 40, 1, 11, 5, 96, 2, 13, 1, 14, 7, 120, 5, 1, 99, 68, 1, 9, 3, 19, 1, 20, 5, 5145000, 3, 88, 80, 23, 5, 48, 2, 1, 323, 52, 5, 6, 1, 7, 1, 116, 7, 60, 5, 124, 1, 2, 1, 1650, 3, 34, 299, 35, 7, 32, 5, 37, 7, 19, 1, 26693550]

cp's OEIS Frontend

A286842 Least k such that the sum of proper divisors of k*n is a prime number, or -1 if no such k exists.

Table of values

List of values