A066753 - cp's OEIS frontend

A066753 a(n) = least natural number k such that n + Sum_{i=1..k} prime(i) is prime if such k exists; = 0 otherwise.

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

[1, 2, 1, 20, 1, 2, 3, 2, 1, 10, 1, 2, 3, 2, 1, 16, 1, 2, 3, 4, 1, 10, 17, 2, 5, 2, 1, 10, 1, 4, 3, 2, 3, 10, 1, 2, 3, 2, 1, 16, 1, 2, 3, 4, 1, 18, 17, 2, 3, 4, 1, 10, 41, 2, 5, 2, 1, 16, 1, 6, 3, 2, 3, 10, 1, 2, 9, 2, 1, 10, 1, 4, 3, 2, 5, 16, 1, 2, 3, 4, 1, 10, 17, 2, 5, 4, 1, 20, 43, 4, 3, 2, 3, 10]

cp's OEIS Frontend

A066753 a(n) = least natural number k such that n + Sum_{i=1..k} prime(i) is prime if such k exists; = 0 otherwise.

Table of values

List of values

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

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

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