A213884 - cp's OEIS frontend

A213884 For the smallest k >= 1, the smallest single-digit j such that (10^k-j)*10^n-1 is prime.

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

[1, 4, 1, 2, 2, 5, 1, 2, 1, 2, 1, 4, 4, 5, 5, 1, 4, 7, 1, 4, 2, 4, 4, 1, 2, 8, 7, 4, 1, 1, 2, 1, 1, 4, 7, 4, 1, 1, 7, 4, 8, 2, 7, 4, 8, 8, 7, 2, 2, 1, 8, 2, 8, 5, 7, 1, 8, 4, 8, 1, 4, 1, 4, 7, 1, 2, 8, 2, 4, 1, 4, 8, 4, 5, 8, 2, 1, 2, 7, 7, 5, 1, 4, 8, 7, 4, 1, 4, 2, 2, 4, 5]

cp's OEIS Frontend

A213884 For the smallest k >= 1, the smallest single-digit j such that (10^k-j)*10^n-1 is prime.

Table of values

List of values

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

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

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