A090464 - cp's OEIS frontend

A090464 Smallest number m such that n with by m sevens appended yields a prime, or -1 if no such m exists.

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

[1, 0, 0, 1, 0, 1, 0, 2, 1, 1, 0, 1, 0, -1, 1, 1, 0, 2, 0, 6, -1, 1, 0, 2, 1, 2, 1, -1, 0, 1, 0, 5, 1, 1, -1, 1, 0, 2, 1, 12, 0, -1, 0, 3, 1, 1, 0, 1, -1, 2, 8, 7, 0, 1, 1, -1, 1, 1, 0, 1, 0, 2, -1, 1, 2, 5, 0, 3, 2, -1, 0, 1, 0, 2, 1, 3, -1, 1, 0, 3, 4, 1, 0, -1, 1, 2, 1, 1, 0, 1, -1, 2, 1, 1]

cp's OEIS Frontend

A090464 Smallest number m such that n with by m sevens appended yields a prime, or -1 if no such m exists.

Table of values

List of values

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

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

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