A117364 - cp's OEIS frontend

A117364 a(n) = largest prime less than the largest prime dividing n (or 1 if there is no such prime).

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

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

cp's OEIS Frontend

A117364 a(n) = largest prime less than the largest prime dividing n (or 1 if there is no such prime).

Table of values

List of values

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

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

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