A212636 - cp's OEIS frontend

A212636 Minimal m >= 1 such that floor((2*n - 1)!!/m) - 2 is prime.

n	a(n)
3	1
4	1
5	3
6	3
7	8
8	1
9	1
10	1
11	5
12	7
13	19
14	7
15	5
16	15
17	7
18	17
19	5
20	3
21	9
22	11
23	63
24	9
25	5
26	1
27	53
28	27
29	51
30	11
31	3
32	11
33	13
34	15
35	17
36	35
37	1
38	17
39	21
40	13
41	139
42	61
43	3
44	13
45	1
46	7
47	147
48	23
49	123
50	47
51	41
52	35
53	11
54	39
55	69
56	21
57	123
58	29
59	27
60	49
61	3
62	9
63	37
64	171
65	57
66	1
67	31
68	37
69	5
70	61
71	27
72	31
73	53

[1, 1, 3, 3, 8, 1, 1, 1, 5, 7, 19, 7, 5, 15, 7, 17, 5, 3, 9, 11, 63, 9, 5, 1, 53, 27, 51, 11, 3, 11, 13, 15, 17, 35, 1, 17, 21, 13, 139, 61, 3, 13, 1, 7, 147, 23, 123, 47, 41, 35, 11, 39, 69, 21, 123, 29, 27, 49, 3, 9, 37, 171, 57, 1, 31, 37, 5, 61, 27, 31, 53]

cp's OEIS Frontend

A212636 Minimal m >= 1 such that floor((2*n - 1)!!/m) - 2 is prime.

Table of values

List of values

n	a(n)
3	1
4	1
5	3
6	3
7	8
8	1
9	1
10	1
11	5
12	7
13	19
14	7
15	5
16	15
17	7
18	17
19	5
20	3
21	9
22	11
23	63
24	9
25	5
26	1
27	53
28	27
29	51
30	11
31	3
32	11
33	13
34	15
35	17
36	35
37	1
38	17
39	21
40	13
41	139
42	61
43	3
44	13
45	1
46	7
47	147
48	23
49	123
50	47
51	41
52	35
53	11
54	39
55	69
56	21
57	123
58	29
59	27
60	49
61	3
62	9
63	37
64	171
65	57
66	1
67	31
68	37
69	5
70	61
71	27
72	31
73	53

n	a(n)
3	1
4	1
5	3
6	3
7	8
8	1
9	1
10	1
11	5
12	7
13	19
14	7
15	5
16	15
17	7
18	17
19	5
20	3
21	9
22	11
23	63
24	9
25	5
26	1
27	53
28	27
29	51
30	11
31	3
32	11
33	13
34	15
35	17
36	35
37	1
38	17
39	21
40	13
41	139
42	61
43	3
44	13
45	1
46	7
47	147
48	23
49	123
50	47
51	41
52	35
53	11
54	39
55	69
56	21
57	123
58	29
59	27
60	49
61	3
62	9
63	37
64	171
65	57
66	1
67	31
68	37
69	5
70	61
71	27
72	31
73	53

n	a(n)
3	1
4	1
5	3
6	3
7	8
8	1
9	1
10	1
11	5
12	7
13	19
14	7
15	5
16	15
17	7
18	17
19	5
20	3
21	9
22	11
23	63
24	9
25	5
26	1
27	53
28	27
29	51
30	11
31	3
32	11
33	13
34	15
35	17
36	35
37	1
38	17
39	21
40	13
41	139
42	61
43	3
44	13
45	1
46	7
47	147
48	23
49	123
50	47
51	41
52	35
53	11
54	39
55	69
56	21
57	123
58	29
59	27
60	49
61	3
62	9
63	37
64	171
65	57
66	1
67	31
68	37
69	5
70	61
71	27
72	31
73	53