A290585 - cp's OEIS frontend

A290585 a(n) is the largest number <= n such that 1 + a(1)a(2)...*a(n) is prime.

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

[1, 2, 3, 3, 4, 6, 6, 4, 7, 7, 3, 10, 13, 12, 10, 9, 13, 14, 15, 16, 13, 21, 22, 11, 25, 26, 27, 17, 29, 23, 7, 11, 30, 24, 34, 1, 1, 1, 1, 1, 1, 1, 1, 1, 45, 39, 23, 48, 32, 25, 44, 49, 53, 31, 1, 1, 1, 1, 59, 46, 53, 55, 62, 40, 62, 59, 46, 41, 9, 62, 59, 64, 1, 1, 1, 1, 1, 1, 1, 80, 57, 78, 80, 1, 85]

cp's OEIS Frontend

A290585 a(n) is the largest number <= n such that 1 + a(1)a(2)...*a(n) is prime.

Table of values

List of values

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

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

cp's OEIS Frontend

A290585 a(n) is the largest number <= n such that 1 + a(1)*a(2)*...*a(n) is prime.

Table of values

List of values

A290585 a(n) is the largest number <= n such that 1 + a(1)a(2)...*a(n) is prime.

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