A259915 - cp's OEIS frontend

A259915 Least positive integer k such that phi(k) and sigma(k*n) are both squares, where phi(.) is Euler's totient function and sigma(m) is the sum of all positive divisors of m.

n	a(n)
1	1
2	85
3	1
4	273
5	34
6	85
7	10
8	364
9	250
10	17
11	2
12	2223
13	204
14	5
15	34
16	546
17	10
18	60
19	680
20	60
21	10
22	1
23	5
24	364
25	48
26	34
27	40
28	451
29	136
30	17
31	10
32	273
33	2
34	5
35	2
36	5089
37	10570
38	1020
39	451
40	10
41	60
42	5
43	1970
44	114
45	114
46	17
47	2
48	4446
49	185
50	8
51	10
52	17
53	5
54	546
55	17
56	285
57	63
58	204
59	8
60	540
61	816
62	5
63	57
64	147744
65	2761
66	1
67	505
68	451
69	5
70	1

[1, 85, 1, 273, 34, 85, 10, 364, 250, 17, 2, 2223, 204, 5, 34, 546, 10, 60, 680, 60, 10, 1, 5, 364, 48, 34, 40, 451, 136, 17, 10, 273, 2, 5, 2, 5089, 10570, 1020, 451, 10, 60, 5, 1970, 114, 114, 17, 2, 4446, 185, 8, 10, 17, 5, 546, 17, 285, 63, 204, 8, 540, 816, 5, 57, 147744, 2761, 1, 505, 451, 5, 1]

cp's OEIS Frontend

A259915 Least positive integer k such that phi(k) and sigma(k*n) are both squares, where phi(.) is Euler's totient function and sigma(m) is the sum of all positive divisors of m.

Table of values

List of values