A336924 - cp's OEIS frontend

A336924 a(n) = spf(1+sigma(n)), where spf is the smallest prime factor and sigma is the sum of divisors function.

n	a(n)
1	2
2	2
3	5
4	2
5	7
6	13
7	3
8	2
9	2
10	19
11	13
12	29
13	3
14	5
15	5
16	2
17	19
18	2
19	3
20	43
21	3
22	37
23	5
24	61
25	2
26	43
27	41
28	3
29	31
30	73
31	3
32	2
33	7
34	5
35	7
36	2
37	3
38	61
39	3
40	7
41	43
42	97
43	3
44	5
45	79
46	73
47	7
48	5
49	2
50	2
51	73
52	3
53	5
54	11
55	73
56	11
57	3
58	7
59	61
60	13
61	3
62	97
63	3
64	2
65	5
66	5
67	3
68	127
69	97
70	5
71	73
72	2
73	3
74	5
75	5
76	3
77	97
78	13
79	3
80	11
81	2
82	127
83	5
84	3
85	109
86	7
87	11
88	181
89	7
90	5
91	113
92	13

[2, 2, 5, 2, 7, 13, 3, 2, 2, 19, 13, 29, 3, 5, 5, 2, 19, 2, 3, 43, 3, 37, 5, 61, 2, 43, 41, 3, 31, 73, 3, 2, 7, 5, 7, 2, 3, 61, 3, 7, 43, 97, 3, 5, 79, 73, 7, 5, 2, 2, 73, 3, 5, 11, 73, 11, 3, 7, 61, 13, 3, 97, 3, 2, 5, 5, 3, 127, 97, 5, 73, 2, 3, 5, 5, 3, 97, 13, 3, 11, 2, 127, 5, 3, 109, 7, 11, 181, 7, 5, 113, 13]

cp's OEIS Frontend

A336924 a(n) = spf(1+sigma(n)), where spf is the smallest prime factor and sigma is the sum of divisors function.

Table of values

List of values

n	a(n)
1	2
2	2
3	5
4	2
5	7
6	13
7	3
8	2
9	2
10	19
11	13
12	29
13	3
14	5
15	5
16	2
17	19
18	2
19	3
20	43
21	3
22	37
23	5
24	61
25	2
26	43
27	41
28	3
29	31
30	73
31	3
32	2
33	7
34	5
35	7
36	2
37	3
38	61
39	3
40	7
41	43
42	97
43	3
44	5
45	79
46	73
47	7
48	5
49	2
50	2
51	73
52	3
53	5
54	11
55	73
56	11
57	3
58	7
59	61
60	13
61	3
62	97
63	3
64	2
65	5
66	5
67	3
68	127
69	97
70	5
71	73
72	2
73	3
74	5
75	5
76	3
77	97
78	13
79	3
80	11
81	2
82	127
83	5
84	3
85	109
86	7
87	11
88	181
89	7
90	5
91	113
92	13

n	a(n)
1	2
2	2
3	5
4	2
5	7
6	13
7	3
8	2
9	2
10	19
11	13
12	29
13	3
14	5
15	5
16	2
17	19
18	2
19	3
20	43
21	3
22	37
23	5
24	61
25	2
26	43
27	41
28	3
29	31
30	73
31	3
32	2
33	7
34	5
35	7
36	2
37	3
38	61
39	3
40	7
41	43
42	97
43	3
44	5
45	79
46	73
47	7
48	5
49	2
50	2
51	73
52	3
53	5
54	11
55	73
56	11
57	3
58	7
59	61
60	13
61	3
62	97
63	3
64	2
65	5
66	5
67	3
68	127
69	97
70	5
71	73
72	2
73	3
74	5
75	5
76	3
77	97
78	13
79	3
80	11
81	2
82	127
83	5
84	3
85	109
86	7
87	11
88	181
89	7
90	5
91	113
92	13

n	a(n)
1	2
2	2
3	5
4	2
5	7
6	13
7	3
8	2
9	2
10	19
11	13
12	29
13	3
14	5
15	5
16	2
17	19
18	2
19	3
20	43
21	3
22	37
23	5
24	61
25	2
26	43
27	41
28	3
29	31
30	73
31	3
32	2
33	7
34	5
35	7
36	2
37	3
38	61
39	3
40	7
41	43
42	97
43	3
44	5
45	79
46	73
47	7
48	5
49	2
50	2
51	73
52	3
53	5
54	11
55	73
56	11
57	3
58	7
59	61
60	13
61	3
62	97
63	3
64	2
65	5
66	5
67	3
68	127
69	97
70	5
71	73
72	2
73	3
74	5
75	5
76	3
77	97
78	13
79	3
80	11
81	2
82	127
83	5
84	3
85	109
86	7
87	11
88	181
89	7
90	5
91	113
92	13