A385681 - cp's OEIS frontend

A385681 a(n) is the least k > 1 such that n^2 == k (mod sopfr(k)) and k^2 == n (mod sopfr(n)), or -1 if there is no such k, where sopfr = A001414.

n	a(n)
2	2
3	3
4	2
5	5
6	4
7	7
8	-1
9	3
10	-1
11	11
12	-1
13	13
14	-1
15	-1
16	4
17	17
18	-1
19	19
20	-1
21	9
22	120
23	23
24	-1
25	5
26	-1
27	3
28	-1
29	29
30	30
31	31
32	-1
33	-1
34	-1
35	-1
36	4
37	37
38	-1
39	-1
40	-1
41	41
42	-1
43	43
44	-1
45	45
46	36
47	47
48	2
49	7
50	-1
51	-1
52	16
53	53
54	-1
55	-1
56	2
57	-1
58	-1
59	59
60	30
61	61
62	-1
63	-1
64	2
65	-1
66	-1
67	67
68	-1
69	2745
70	70
71	71
72	60
73	73
74	-1
75	150
76	-1
77	-1
78	-1

[2, 3, 2, 5, 4, 7, -1, 3, -1, 11, -1, 13, -1, -1, 4, 17, -1, 19, -1, 9, 120, 23, -1, 5, -1, 3, -1, 29, 30, 31, -1, -1, -1, -1, 4, 37, -1, -1, -1, 41, -1, 43, -1, 45, 36, 47, 2, 7, -1, -1, 16, 53, -1, -1, 2, -1, -1, 59, 30, 61, -1, -1, 2, -1, -1, 67, -1, 2745, 70, 71, 60, 73, -1, 150, -1, -1, -1]

cp's OEIS Frontend

A385681 a(n) is the least k > 1 such that n^2 == k (mod sopfr(k)) and k^2 == n (mod sopfr(n)), or -1 if there is no such k, where sopfr = A001414.

Table of values

List of values