A339872 - cp's OEIS frontend

A339872 Index k of the least prime(k) such that prime(k)-adic valuation of phi(n) exceeds the prime(k)-adic valuation of n-1, or 0 if no such k exists (for example, when n = 1 or a prime).

n	a(n)
1	0
2	0
3	0
4	1
5	0
6	1
7	0
8	1
9	2
10	1
11	0
12	1
13	0
14	1
15	1
16	1
17	0
18	1
19	0
20	1
21	2
22	1
23	0
24	1
25	3
26	1
27	2
28	1
29	0
30	1
31	0
32	1
33	3
34	1
35	1
36	1
37	0
38	1
39	1
40	1
41	0
42	1
43	0
44	1
45	1
46	1
47	0
48	1
49	4
50	1
51	1
52	1
53	0
54	1
55	1
56	1
57	2
58	1
59	0
60	1
61	0
62	1
63	1
64	1
65	2
66	1
67	0
68	1
69	5
70	1
71	0
72	1
73	0
74	1
75	1
76	1
77	2
78	1
79	0
80	1
81	2
82	1
83	0
84	1
85	1
86	1
87	1
88	1
89	0
90	1
91	1
92	1
93	2
94	1
95	1
96	1
97	0
98	1
99	1
100	1
101	0
102	1
103	0
104	1
105	1

[0, 0, 0, 1, 0, 1, 0, 1, 2, 1, 0, 1, 0, 1, 1, 1, 0, 1, 0, 1, 2, 1, 0, 1, 3, 1, 2, 1, 0, 1, 0, 1, 3, 1, 1, 1, 0, 1, 1, 1, 0, 1, 0, 1, 1, 1, 0, 1, 4, 1, 1, 1, 0, 1, 1, 1, 2, 1, 0, 1, 0, 1, 1, 1, 2, 1, 0, 1, 5, 1, 0, 1, 0, 1, 1, 1, 2, 1, 0, 1, 2, 1, 0, 1, 1, 1, 1, 1, 0, 1, 1, 1, 2, 1, 1, 1, 0, 1, 1, 1, 0, 1, 0, 1, 1]

cp's OEIS Frontend

A339872 Index k of the least prime(k) such that prime(k)-adic valuation of phi(n) exceeds the prime(k)-adic valuation of n-1, or 0 if no such k exists (for example, when n = 1 or a prime).

Table of values

List of values

n	a(n)
1	0
2	0
3	0
4	1
5	0
6	1
7	0
8	1
9	2
10	1
11	0
12	1
13	0
14	1
15	1
16	1
17	0
18	1
19	0
20	1
21	2
22	1
23	0
24	1
25	3
26	1
27	2
28	1
29	0
30	1
31	0
32	1
33	3
34	1
35	1
36	1
37	0
38	1
39	1
40	1
41	0
42	1
43	0
44	1
45	1
46	1
47	0
48	1
49	4
50	1
51	1
52	1
53	0
54	1
55	1
56	1
57	2
58	1
59	0
60	1
61	0
62	1
63	1
64	1
65	2
66	1
67	0
68	1
69	5
70	1
71	0
72	1
73	0
74	1
75	1
76	1
77	2
78	1
79	0
80	1
81	2
82	1
83	0
84	1
85	1
86	1
87	1
88	1
89	0
90	1
91	1
92	1
93	2
94	1
95	1
96	1
97	0
98	1
99	1
100	1
101	0
102	1
103	0
104	1
105	1

n	a(n)
1	0
2	0
3	0
4	1
5	0
6	1
7	0
8	1
9	2
10	1
11	0
12	1
13	0
14	1
15	1
16	1
17	0
18	1
19	0
20	1
21	2
22	1
23	0
24	1
25	3
26	1
27	2
28	1
29	0
30	1
31	0
32	1
33	3
34	1
35	1
36	1
37	0
38	1
39	1
40	1
41	0
42	1
43	0
44	1
45	1
46	1
47	0
48	1
49	4
50	1
51	1
52	1
53	0
54	1
55	1
56	1
57	2
58	1
59	0
60	1
61	0
62	1
63	1
64	1
65	2
66	1
67	0
68	1
69	5
70	1
71	0
72	1
73	0
74	1
75	1
76	1
77	2
78	1
79	0
80	1
81	2
82	1
83	0
84	1
85	1
86	1
87	1
88	1
89	0
90	1
91	1
92	1
93	2
94	1
95	1
96	1
97	0
98	1
99	1
100	1
101	0
102	1
103	0
104	1
105	1

n	a(n)
1	0
2	0
3	0
4	1
5	0
6	1
7	0
8	1
9	2
10	1
11	0
12	1
13	0
14	1
15	1
16	1
17	0
18	1
19	0
20	1
21	2
22	1
23	0
24	1
25	3
26	1
27	2
28	1
29	0
30	1
31	0
32	1
33	3
34	1
35	1
36	1
37	0
38	1
39	1
40	1
41	0
42	1
43	0
44	1
45	1
46	1
47	0
48	1
49	4
50	1
51	1
52	1
53	0
54	1
55	1
56	1
57	2
58	1
59	0
60	1
61	0
62	1
63	1
64	1
65	2
66	1
67	0
68	1
69	5
70	1
71	0
72	1
73	0
74	1
75	1
76	1
77	2
78	1
79	0
80	1
81	2
82	1
83	0
84	1
85	1
86	1
87	1
88	1
89	0
90	1
91	1
92	1
93	2
94	1
95	1
96	1
97	0
98	1
99	1
100	1
101	0
102	1
103	0
104	1
105	1