A238901 - cp's OEIS frontend

A238901 a(n) is the smallest k, 1<=k<=(p_n-3)/2, such that sum{i=1,...,p_n-2k-1} 2^(i-1) Binomial(k-1+i, k)/p_n is prime; a(n)=0, if such k does not exist.

n	a(n)
4	1
5	1
6	1
7	6
8	2
9	5
10	10
11	1
12	3
13	11
14	8
15	13
16	21
17	5
18	8
19	29
20	19
21	19
22	37
23	0
24	11
25	11
26	45
27	42
28	25
29	11
30	41
31	7
32	62
33	39
34	55
35	70
36	29
37	60
38	49
39	24
40	1
41	0
42	47
43	73
44	49
45	78
46	52
47	11
48	80
49	80
50	28
51	32
52	0
53	92
54	117
55	112
56	43
57	102
58	19
59	97
60	47
61	38
62	140
63	51
64	152
65	44
66	43
67	141

[1, 1, 1, 6, 2, 5, 10, 1, 3, 11, 8, 13, 21, 5, 8, 29, 19, 19, 37, 0, 11, 11, 45, 42, 25, 11, 41, 7, 62, 39, 55, 70, 29, 60, 49, 24, 1, 0, 47, 73, 49, 78, 52, 11, 80, 80, 28, 32, 0, 92, 117, 112, 43, 102, 19, 97, 47, 38, 140, 51, 152, 44, 43, 141]

cp's OEIS Frontend

A238901 a(n) is the smallest k, 1<=k<=(p_n-3)/2, such that sum{i=1,...,p_n-2k-1} 2^(i-1) Binomial(k-1+i, k)/p_n is prime; a(n)=0, if such k does not exist.

Table of values

List of values

n	a(n)
4	1
5	1
6	1
7	6
8	2
9	5
10	10
11	1
12	3
13	11
14	8
15	13
16	21
17	5
18	8
19	29
20	19
21	19
22	37
23	0
24	11
25	11
26	45
27	42
28	25
29	11
30	41
31	7
32	62
33	39
34	55
35	70
36	29
37	60
38	49
39	24
40	1
41	0
42	47
43	73
44	49
45	78
46	52
47	11
48	80
49	80
50	28
51	32
52	0
53	92
54	117
55	112
56	43
57	102
58	19
59	97
60	47
61	38
62	140
63	51
64	152
65	44
66	43
67	141

n	a(n)
4	1
5	1
6	1
7	6
8	2
9	5
10	10
11	1
12	3
13	11
14	8
15	13
16	21
17	5
18	8
19	29
20	19
21	19
22	37
23	0
24	11
25	11
26	45
27	42
28	25
29	11
30	41
31	7
32	62
33	39
34	55
35	70
36	29
37	60
38	49
39	24
40	1
41	0
42	47
43	73
44	49
45	78
46	52
47	11
48	80
49	80
50	28
51	32
52	0
53	92
54	117
55	112
56	43
57	102
58	19
59	97
60	47
61	38
62	140
63	51
64	152
65	44
66	43
67	141

n	a(n)
4	1
5	1
6	1
7	6
8	2
9	5
10	10
11	1
12	3
13	11
14	8
15	13
16	21
17	5
18	8
19	29
20	19
21	19
22	37
23	0
24	11
25	11
26	45
27	42
28	25
29	11
30	41
31	7
32	62
33	39
34	55
35	70
36	29
37	60
38	49
39	24
40	1
41	0
42	47
43	73
44	49
45	78
46	52
47	11
48	80
49	80
50	28
51	32
52	0
53	92
54	117
55	112
56	43
57	102
58	19
59	97
60	47
61	38
62	140
63	51
64	152
65	44
66	43
67	141