A178380 - cp's OEIS frontend

A178380 The greatest common prime divisor of n, A000032(n)-1 and A001608(n), or 1 if no such greatest common divisor exists.

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

[2, 3, 2, 5, 1, 7, 2, 3, 1, 11, 1, 13, 1, 1, 2, 17, 1, 19, 1, 1, 2, 23, 1, 5, 1, 3, 1, 29, 1, 31, 2, 1, 1, 1, 1, 37, 1, 1, 1, 41, 1, 43, 2, 1, 2, 47, 1, 7, 2, 1, 1, 53, 1, 1, 1, 1, 2, 59, 1, 61, 1, 1, 2, 1, 1, 67, 1, 1, 1, 71, 1, 73, 2, 1, 1, 1, 1, 79, 1, 3, 1, 83, 1, 1, 2, 1, 2, 89, 1]

cp's OEIS Frontend

A178380 The greatest common prime divisor of n, A000032(n)-1 and A001608(n), or 1 if no such greatest common divisor exists.

Table of values

List of values

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

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

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