A066868 - cp's OEIS frontend

A066868 a(n) is the least k such that n + Sum_{i=1..k} A005385(i) is prime; or 0 if none exists.

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

[2, 1, 10, 5, 2, 1, 2, 1, 12, 5, 2, 1, 4, 1, 4, 5, 2, 1, 2, 3, 4, 7, 12, 1, 2, 1, 4, 7, 2, 3, 2, 1, 4, 5, 2, 1, 4, 1, 6, 17, 2, 1, 4, 3, 6, 5, 2, 1, 2, 3, 4, 11, 12, 1, 2, 1, 4, 5, 2, 3, 2, 1, 4, 5, 14, 1, 2, 1, 10, 5, 2, 7, 10, 1, 6, 7, 2, 1, 8, 3, 4, 7, 26, 1]

cp's OEIS Frontend

A066868 a(n) is the least k such that n + Sum_{i=1..k} A005385(i) is prime; or 0 if none exists.

Table of values

List of values

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

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

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