A023509 - cp's OEIS frontend

A023509 Greatest prime divisor of prime(n) + 1.

n	a(n)
1	3
2	2
3	3
4	2
5	3
6	7
7	3
8	5
9	3
10	5
11	2
12	19
13	7
14	11
15	3
16	3
17	5
18	31
19	17
20	3
21	37
22	5
23	7
24	5
25	7
26	17
27	13
28	3
29	11
30	19
31	2
32	11
33	23
34	7
35	5
36	19
37	79
38	41
39	7
40	29
41	5
42	13
43	3
44	97
45	11
46	5
47	53
48	7
49	19
50	23
51	13
52	5
53	11
54	7
55	43
56	11
57	5
58	17
59	139
60	47
61	71
62	7
63	11
64	13
65	157
66	53
67	83
68	13
69	29
70	7
71	59
72	5
73	23
74	17
75	19
76	3
77	13

[3, 2, 3, 2, 3, 7, 3, 5, 3, 5, 2, 19, 7, 11, 3, 3, 5, 31, 17, 3, 37, 5, 7, 5, 7, 17, 13, 3, 11, 19, 2, 11, 23, 7, 5, 19, 79, 41, 7, 29, 5, 13, 3, 97, 11, 5, 53, 7, 19, 23, 13, 5, 11, 7, 43, 11, 5, 17, 139, 47, 71, 7, 11, 13, 157, 53, 83, 13, 29, 7, 59, 5, 23, 17, 19, 3, 13]

cp's OEIS Frontend

A023509 Greatest prime divisor of prime(n) + 1.

Table of values

List of values

n	a(n)
1	3
2	2
3	3
4	2
5	3
6	7
7	3
8	5
9	3
10	5
11	2
12	19
13	7
14	11
15	3
16	3
17	5
18	31
19	17
20	3
21	37
22	5
23	7
24	5
25	7
26	17
27	13
28	3
29	11
30	19
31	2
32	11
33	23
34	7
35	5
36	19
37	79
38	41
39	7
40	29
41	5
42	13
43	3
44	97
45	11
46	5
47	53
48	7
49	19
50	23
51	13
52	5
53	11
54	7
55	43
56	11
57	5
58	17
59	139
60	47
61	71
62	7
63	11
64	13
65	157
66	53
67	83
68	13
69	29
70	7
71	59
72	5
73	23
74	17
75	19
76	3
77	13

n	a(n)
1	3
2	2
3	3
4	2
5	3
6	7
7	3
8	5
9	3
10	5
11	2
12	19
13	7
14	11
15	3
16	3
17	5
18	31
19	17
20	3
21	37
22	5
23	7
24	5
25	7
26	17
27	13
28	3
29	11
30	19
31	2
32	11
33	23
34	7
35	5
36	19
37	79
38	41
39	7
40	29
41	5
42	13
43	3
44	97
45	11
46	5
47	53
48	7
49	19
50	23
51	13
52	5
53	11
54	7
55	43
56	11
57	5
58	17
59	139
60	47
61	71
62	7
63	11
64	13
65	157
66	53
67	83
68	13
69	29
70	7
71	59
72	5
73	23
74	17
75	19
76	3
77	13

n	a(n)
1	3
2	2
3	3
4	2
5	3
6	7
7	3
8	5
9	3
10	5
11	2
12	19
13	7
14	11
15	3
16	3
17	5
18	31
19	17
20	3
21	37
22	5
23	7
24	5
25	7
26	17
27	13
28	3
29	11
30	19
31	2
32	11
33	23
34	7
35	5
36	19
37	79
38	41
39	7
40	29
41	5
42	13
43	3
44	97
45	11
46	5
47	53
48	7
49	19
50	23
51	13
52	5
53	11
54	7
55	43
56	11
57	5
58	17
59	139
60	47
61	71
62	7
63	11
64	13
65	157
66	53
67	83
68	13
69	29
70	7
71	59
72	5
73	23
74	17
75	19
76	3
77	13