A072341 - cp's OEIS frontend

A072341 a(n) = the least natural number k such that k*sigma(n) + 1 is prime.

n	a(n)
1	1
2	2
3	1
4	4
5	1
6	1
7	2
8	2
9	4
10	1
11	1
12	1
13	2
14	3
15	3
16	10
17	1
18	2
19	2
20	1
21	3
22	1
23	3
24	1
25	10
26	1
27	1
28	2
29	1
30	1
31	3
32	2
33	2
34	2
35	2
36	6
37	5
38	1
39	2
40	2
41	1
42	1
43	2
44	4
45	1
46	1
47	2
48	3
49	4
50	4
51	1
52	2
53	2
54	2
55	1
56	2
57	3
58	2
59	1
60	2
61	5
62	1
63	3
64	4
65	4
66	3
67	2
68	1
69	1
70	3
71	1
72	6
73	2
74	2
75	3
76	2
77	1
78	2
79	3
80	2
81	6
82	1
83	4
84	2
85	1
86	3
87	2
88	1
89	2
90	4
91	1
92	2
93	2
94	3
95	2
96	3
97	2
98	12
99	1
100	6
101	1
102	2
103	3

[1, 2, 1, 4, 1, 1, 2, 2, 4, 1, 1, 1, 2, 3, 3, 10, 1, 2, 2, 1, 3, 1, 3, 1, 10, 1, 1, 2, 1, 1, 3, 2, 2, 2, 2, 6, 5, 1, 2, 2, 1, 1, 2, 4, 1, 1, 2, 3, 4, 4, 1, 2, 2, 2, 1, 2, 3, 2, 1, 2, 5, 1, 3, 4, 4, 3, 2, 1, 1, 3, 1, 6, 2, 2, 3, 2, 1, 2, 3, 2, 6, 1, 4, 2, 1, 3, 2, 1, 2, 4, 1, 2, 2, 3, 2, 3, 2, 12, 1, 6, 1, 2, 3]

cp's OEIS Frontend

A072341 a(n) = the least natural number k such that k*sigma(n) + 1 is prime.

Table of values

List of values

n	a(n)
1	1
2	2
3	1
4	4
5	1
6	1
7	2
8	2
9	4
10	1
11	1
12	1
13	2
14	3
15	3
16	10
17	1
18	2
19	2
20	1
21	3
22	1
23	3
24	1
25	10
26	1
27	1
28	2
29	1
30	1
31	3
32	2
33	2
34	2
35	2
36	6
37	5
38	1
39	2
40	2
41	1
42	1
43	2
44	4
45	1
46	1
47	2
48	3
49	4
50	4
51	1
52	2
53	2
54	2
55	1
56	2
57	3
58	2
59	1
60	2
61	5
62	1
63	3
64	4
65	4
66	3
67	2
68	1
69	1
70	3
71	1
72	6
73	2
74	2
75	3
76	2
77	1
78	2
79	3
80	2
81	6
82	1
83	4
84	2
85	1
86	3
87	2
88	1
89	2
90	4
91	1
92	2
93	2
94	3
95	2
96	3
97	2
98	12
99	1
100	6
101	1
102	2
103	3

n	a(n)
1	1
2	2
3	1
4	4
5	1
6	1
7	2
8	2
9	4
10	1
11	1
12	1
13	2
14	3
15	3
16	10
17	1
18	2
19	2
20	1
21	3
22	1
23	3
24	1
25	10
26	1
27	1
28	2
29	1
30	1
31	3
32	2
33	2
34	2
35	2
36	6
37	5
38	1
39	2
40	2
41	1
42	1
43	2
44	4
45	1
46	1
47	2
48	3
49	4
50	4
51	1
52	2
53	2
54	2
55	1
56	2
57	3
58	2
59	1
60	2
61	5
62	1
63	3
64	4
65	4
66	3
67	2
68	1
69	1
70	3
71	1
72	6
73	2
74	2
75	3
76	2
77	1
78	2
79	3
80	2
81	6
82	1
83	4
84	2
85	1
86	3
87	2
88	1
89	2
90	4
91	1
92	2
93	2
94	3
95	2
96	3
97	2
98	12
99	1
100	6
101	1
102	2
103	3

n	a(n)
1	1
2	2
3	1
4	4
5	1
6	1
7	2
8	2
9	4
10	1
11	1
12	1
13	2
14	3
15	3
16	10
17	1
18	2
19	2
20	1
21	3
22	1
23	3
24	1
25	10
26	1
27	1
28	2
29	1
30	1
31	3
32	2
33	2
34	2
35	2
36	6
37	5
38	1
39	2
40	2
41	1
42	1
43	2
44	4
45	1
46	1
47	2
48	3
49	4
50	4
51	1
52	2
53	2
54	2
55	1
56	2
57	3
58	2
59	1
60	2
61	5
62	1
63	3
64	4
65	4
66	3
67	2
68	1
69	1
70	3
71	1
72	6
73	2
74	2
75	3
76	2
77	1
78	2
79	3
80	2
81	6
82	1
83	4
84	2
85	1
86	3
87	2
88	1
89	2
90	4
91	1
92	2
93	2
94	3
95	2
96	3
97	2
98	12
99	1
100	6
101	1
102	2
103	3