A309727 - cp's OEIS frontend

A309727 a(n) is the least integer k such that for some iteration of sigma applied to k, one gets the n-th term of A002191, the list of possible values for the function sum of divisors.

n	a(n)
1	1
2	2
3	2
4	5
5	2
6	2
7	5
8	9
9	9
10	2
11	10
12	19
13	2
14	5
15	29
16	16
17	16
18	22
19	37
20	10
21	27
22	19
23	43
24	33
25	34
26	5
27	49
28	2
29	61
30	16
31	67
32	29
33	73
34	45
35	49
36	43
37	27
38	22
39	50
40	19
41	52
42	101
43	16
44	85
45	109
46	22
47	73
48	5
49	81
50	33
51	67
52	64
53	50
54	86
55	81
56	137
57	76
58	66
59	149
60	111
61	99
62	157
63	81
64	106
65	163
66	2
67	52
68	173
69	129

[1, 2, 2, 5, 2, 2, 5, 9, 9, 2, 10, 19, 2, 5, 29, 16, 16, 22, 37, 10, 27, 19, 43, 33, 34, 5, 49, 2, 61, 16, 67, 29, 73, 45, 49, 43, 27, 22, 50, 19, 52, 101, 16, 85, 109, 22, 73, 5, 81, 33, 67, 64, 50, 86, 81, 137, 76, 66, 149, 111, 99, 157, 81, 106, 163, 2, 52, 173, 129]

cp's OEIS Frontend

A309727 a(n) is the least integer k such that for some iteration of sigma applied to k, one gets the n-th term of A002191, the list of possible values for the function sum of divisors.

Table of values

List of values

n	a(n)
1	1
2	2
3	2
4	5
5	2
6	2
7	5
8	9
9	9
10	2
11	10
12	19
13	2
14	5
15	29
16	16
17	16
18	22
19	37
20	10
21	27
22	19
23	43
24	33
25	34
26	5
27	49
28	2
29	61
30	16
31	67
32	29
33	73
34	45
35	49
36	43
37	27
38	22
39	50
40	19
41	52
42	101
43	16
44	85
45	109
46	22
47	73
48	5
49	81
50	33
51	67
52	64
53	50
54	86
55	81
56	137
57	76
58	66
59	149
60	111
61	99
62	157
63	81
64	106
65	163
66	2
67	52
68	173
69	129

n	a(n)
1	1
2	2
3	2
4	5
5	2
6	2
7	5
8	9
9	9
10	2
11	10
12	19
13	2
14	5
15	29
16	16
17	16
18	22
19	37
20	10
21	27
22	19
23	43
24	33
25	34
26	5
27	49
28	2
29	61
30	16
31	67
32	29
33	73
34	45
35	49
36	43
37	27
38	22
39	50
40	19
41	52
42	101
43	16
44	85
45	109
46	22
47	73
48	5
49	81
50	33
51	67
52	64
53	50
54	86
55	81
56	137
57	76
58	66
59	149
60	111
61	99
62	157
63	81
64	106
65	163
66	2
67	52
68	173
69	129

n	a(n)
1	1
2	2
3	2
4	5
5	2
6	2
7	5
8	9
9	9
10	2
11	10
12	19
13	2
14	5
15	29
16	16
17	16
18	22
19	37
20	10
21	27
22	19
23	43
24	33
25	34
26	5
27	49
28	2
29	61
30	16
31	67
32	29
33	73
34	45
35	49
36	43
37	27
38	22
39	50
40	19
41	52
42	101
43	16
44	85
45	109
46	22
47	73
48	5
49	81
50	33
51	67
52	64
53	50
54	86
55	81
56	137
57	76
58	66
59	149
60	111
61	99
62	157
63	81
64	106
65	163
66	2
67	52
68	173
69	129