A378641 - cp's OEIS frontend

A378641 Largest m <= n such that phi(m) does not divide n, or -1 if no such m exists, where phi is the Euler totient function (A000010).

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

[-1, -1, 3, -1, 5, 5, 7, 7, 9, 10, 11, 11, 13, 14, 15, 14, 17, 17, 19, 20, 21, 22, 23, 23, 25, 26, 27, 28, 29, 30, 31, 31, 33, 34, 35, 35, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 47, 49, 50, 51, 52, 53, 53, 55, 56, 57, 58, 59, 60, 61, 62, 63, 63, 65, 66, 67, 68, 69]

cp's OEIS Frontend

A378641 Largest m <= n such that phi(m) does not divide n, or -1 if no such m exists, where phi is the Euler totient function (A000010).

Table of values

List of values

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

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

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