A321392 - cp's OEIS frontend

A321392 a(n) is the number of bases b > 1 such that prime(n) + digitsum(prime(n), base b) is prime (where prime(n) denotes the n-th prime number).

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

[1, 1, 2, 1, 2, 3, 4, 4, 3, 5, 6, 7, 7, 7, 7, 10, 11, 10, 12, 11, 11, 12, 11, 13, 16, 14, 13, 10, 14, 13, 21, 19, 19, 17, 20, 21, 24, 26, 25, 25, 25, 23, 26, 26, 24, 26, 29, 33, 27, 30, 31, 28, 32, 33, 32, 34, 34, 34, 32, 31, 34, 37, 37, 41, 36, 38, 41, 44, 45]

cp's OEIS Frontend

A321392 a(n) is the number of bases b > 1 such that prime(n) + digitsum(prime(n), base b) is prime (where prime(n) denotes the n-th prime number).

Table of values

List of values

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

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

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