A309653 - cp's OEIS frontend

A309653 Composite numbers k such that phi(k) * psi(k) + 1 is a perfect square, where phi is the Euler totient function (A000010) and psi is the Dedekind psi function (A001615).

n	a(n)
1	6
2	8
3	20
4	22
5	33
6	69
7	82
8	156
9	171
10	190
11	198
12	295
13	354
14	451
15	581
16	664
17	1119
18	1142
19	1175
20	1184
21	2812
22	2893
23	4043
24	4163
25	4262
26	4581
27	5090
28	6964
29	7018
30	12977
31	14927
32	15026
33	15753
34	19105
35	22828
36	22926
37	25132
38	25369
39	28919
40	29746
41	38013
42	39146
43	47932
44	74666
45	80375

[6, 8, 20, 22, 33, 69, 82, 156, 171, 190, 198, 295, 354, 451, 581, 664, 1119, 1142, 1175, 1184, 2812, 2893, 4043, 4163, 4262, 4581, 5090, 6964, 7018, 12977, 14927, 15026, 15753, 19105, 22828, 22926, 25132, 25369, 28919, 29746, 38013, 39146, 47932, 74666, 80375]

cp's OEIS Frontend

A309653 Composite numbers k such that phi(k) * psi(k) + 1 is a perfect square, where phi is the Euler totient function (A000010) and psi is the Dedekind psi function (A001615).

Table of values

List of values