A225216 - cp's OEIS frontend

A225216 Let p = n-th prime. Then a(n) = number of primes generated by prepending to the digits of p the digits of q, where q is any prime less than p.

n	a(n)
1	0
2	1
3	0
4	1
5	2
6	1
7	2
8	2
9	4
10	2
11	2
12	2
13	4
14	1
15	4
16	5
17	4
18	3
19	4
20	5
21	6
22	4
23	5
24	5
25	6
26	5
27	6
28	5
29	3
30	8
31	4
32	6
33	8
34	7
35	8
36	7
37	5
38	6
39	8
40	8
41	4
42	9
43	7
44	5
45	10
46	5
47	9
48	5
49	8
50	8
51	10
52	8
53	8
54	14
55	10
56	7
57	14
58	8
59	8
60	11
61	10
62	13
63	8
64	10
65	10
66	10
67	11
68	12
69	13
70	8
71	11
72	14
73	12
74	11
75	13
76	13
77	13
78	16

[0, 1, 0, 1, 2, 1, 2, 2, 4, 2, 2, 2, 4, 1, 4, 5, 4, 3, 4, 5, 6, 4, 5, 5, 6, 5, 6, 5, 3, 8, 4, 6, 8, 7, 8, 7, 5, 6, 8, 8, 4, 9, 7, 5, 10, 5, 9, 5, 8, 8, 10, 8, 8, 14, 10, 7, 14, 8, 8, 11, 10, 13, 8, 10, 10, 10, 11, 12, 13, 8, 11, 14, 12, 11, 13, 13, 13, 16]

cp's OEIS Frontend

A225216 Let p = n-th prime. Then a(n) = number of primes generated by prepending to the digits of p the digits of q, where q is any prime less than p.

Table of values

List of values

n	a(n)
1	0
2	1
3	0
4	1
5	2
6	1
7	2
8	2
9	4
10	2
11	2
12	2
13	4
14	1
15	4
16	5
17	4
18	3
19	4
20	5
21	6
22	4
23	5
24	5
25	6
26	5
27	6
28	5
29	3
30	8
31	4
32	6
33	8
34	7
35	8
36	7
37	5
38	6
39	8
40	8
41	4
42	9
43	7
44	5
45	10
46	5
47	9
48	5
49	8
50	8
51	10
52	8
53	8
54	14
55	10
56	7
57	14
58	8
59	8
60	11
61	10
62	13
63	8
64	10
65	10
66	10
67	11
68	12
69	13
70	8
71	11
72	14
73	12
74	11
75	13
76	13
77	13
78	16

n	a(n)
1	0
2	1
3	0
4	1
5	2
6	1
7	2
8	2
9	4
10	2
11	2
12	2
13	4
14	1
15	4
16	5
17	4
18	3
19	4
20	5
21	6
22	4
23	5
24	5
25	6
26	5
27	6
28	5
29	3
30	8
31	4
32	6
33	8
34	7
35	8
36	7
37	5
38	6
39	8
40	8
41	4
42	9
43	7
44	5
45	10
46	5
47	9
48	5
49	8
50	8
51	10
52	8
53	8
54	14
55	10
56	7
57	14
58	8
59	8
60	11
61	10
62	13
63	8
64	10
65	10
66	10
67	11
68	12
69	13
70	8
71	11
72	14
73	12
74	11
75	13
76	13
77	13
78	16

n	a(n)
1	0
2	1
3	0
4	1
5	2
6	1
7	2
8	2
9	4
10	2
11	2
12	2
13	4
14	1
15	4
16	5
17	4
18	3
19	4
20	5
21	6
22	4
23	5
24	5
25	6
26	5
27	6
28	5
29	3
30	8
31	4
32	6
33	8
34	7
35	8
36	7
37	5
38	6
39	8
40	8
41	4
42	9
43	7
44	5
45	10
46	5
47	9
48	5
49	8
50	8
51	10
52	8
53	8
54	14
55	10
56	7
57	14
58	8
59	8
60	11
61	10
62	13
63	8
64	10
65	10
66	10
67	11
68	12
69	13
70	8
71	11
72	14
73	12
74	11
75	13
76	13
77	13
78	16