A079277 - cp's OEIS frontend

A079277 Largest integer k < n such that any prime factor of k is also a prime factor of n.

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

[1, 1, 2, 1, 4, 1, 4, 3, 8, 1, 9, 1, 8, 9, 8, 1, 16, 1, 16, 9, 16, 1, 18, 5, 16, 9, 16, 1, 27, 1, 16, 27, 32, 25, 32, 1, 32, 27, 32, 1, 36, 1, 32, 27, 32, 1, 36, 7, 40, 27, 32, 1, 48, 25, 49, 27, 32, 1, 54, 1, 32, 49, 32, 25, 64, 1, 64, 27, 64, 1, 64, 1, 64, 45, 64, 49, 72, 1, 64, 27]

cp's OEIS Frontend

A079277 Largest integer k < n such that any prime factor of k is also a prime factor of n.

Table of values

List of values

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

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

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