A173291 - cp's OEIS frontend

A173291 Smallest prime p such that the concatenation of p and prime(n) is a prime, or 0 if no other number exists.

n	a(n)
1	0
2	2
3	0
4	3
5	2
6	3
7	3
8	7
9	2
10	2
11	3
12	3
13	2
14	7
15	3
16	3
17	3
18	7
19	3
20	2
21	3
22	3
23	2
24	3
25	3
26	5
27	7
28	5
29	3
30	2
31	7
32	2
33	2
34	19
35	11
36	7
37	19
38	3
39	3
40	9
41	2
42	3
43	3
44	7
45	5
46	37
47	7
48	31
49	5
50	3
51	5
52	2
53	13
54	2
55	3
56	41
57	2
58	3
59	31
60	2
61	7
62	2
63	3
64	2
65	3
66	11
67	3
68	13
69	2
70	7
71	11
72	3
73	13
74	3
75	19
76	2
77	2
78	13
79	17
80	37
81	5
82	13
83	5
84	3
85	139
86	5
87	3
88	3
89	3
90	3
91	2
92	5
93	7
94	3
95	3

[0, 2, 0, 3, 2, 3, 3, 7, 2, 2, 3, 3, 2, 7, 3, 3, 3, 7, 3, 2, 3, 3, 2, 3, 3, 5, 7, 5, 3, 2, 7, 2, 2, 19, 11, 7, 19, 3, 3, 9, 2, 3, 3, 7, 5, 37, 7, 31, 5, 3, 5, 2, 13, 2, 3, 41, 2, 3, 31, 2, 7, 2, 3, 2, 3, 11, 3, 13, 2, 7, 11, 3, 13, 3, 19, 2, 2, 13, 17, 37, 5, 13, 5, 3, 139, 5, 3, 3, 3, 3, 2, 5, 7, 3, 3]

cp's OEIS Frontend

A173291 Smallest prime p such that the concatenation of p and prime(n) is a prime, or 0 if no other number exists.

Table of values

List of values

n	a(n)
1	0
2	2
3	0
4	3
5	2
6	3
7	3
8	7
9	2
10	2
11	3
12	3
13	2
14	7
15	3
16	3
17	3
18	7
19	3
20	2
21	3
22	3
23	2
24	3
25	3
26	5
27	7
28	5
29	3
30	2
31	7
32	2
33	2
34	19
35	11
36	7
37	19
38	3
39	3
40	9
41	2
42	3
43	3
44	7
45	5
46	37
47	7
48	31
49	5
50	3
51	5
52	2
53	13
54	2
55	3
56	41
57	2
58	3
59	31
60	2
61	7
62	2
63	3
64	2
65	3
66	11
67	3
68	13
69	2
70	7
71	11
72	3
73	13
74	3
75	19
76	2
77	2
78	13
79	17
80	37
81	5
82	13
83	5
84	3
85	139
86	5
87	3
88	3
89	3
90	3
91	2
92	5
93	7
94	3
95	3

n	a(n)
1	0
2	2
3	0
4	3
5	2
6	3
7	3
8	7
9	2
10	2
11	3
12	3
13	2
14	7
15	3
16	3
17	3
18	7
19	3
20	2
21	3
22	3
23	2
24	3
25	3
26	5
27	7
28	5
29	3
30	2
31	7
32	2
33	2
34	19
35	11
36	7
37	19
38	3
39	3
40	9
41	2
42	3
43	3
44	7
45	5
46	37
47	7
48	31
49	5
50	3
51	5
52	2
53	13
54	2
55	3
56	41
57	2
58	3
59	31
60	2
61	7
62	2
63	3
64	2
65	3
66	11
67	3
68	13
69	2
70	7
71	11
72	3
73	13
74	3
75	19
76	2
77	2
78	13
79	17
80	37
81	5
82	13
83	5
84	3
85	139
86	5
87	3
88	3
89	3
90	3
91	2
92	5
93	7
94	3
95	3

n	a(n)
1	0
2	2
3	0
4	3
5	2
6	3
7	3
8	7
9	2
10	2
11	3
12	3
13	2
14	7
15	3
16	3
17	3
18	7
19	3
20	2
21	3
22	3
23	2
24	3
25	3
26	5
27	7
28	5
29	3
30	2
31	7
32	2
33	2
34	19
35	11
36	7
37	19
38	3
39	3
40	9
41	2
42	3
43	3
44	7
45	5
46	37
47	7
48	31
49	5
50	3
51	5
52	2
53	13
54	2
55	3
56	41
57	2
58	3
59	31
60	2
61	7
62	2
63	3
64	2
65	3
66	11
67	3
68	13
69	2
70	7
71	11
72	3
73	13
74	3
75	19
76	2
77	2
78	13
79	17
80	37
81	5
82	13
83	5
84	3
85	139
86	5
87	3
88	3
89	3
90	3
91	2
92	5
93	7
94	3
95	3