A072869 - cp's OEIS frontend

A072869 a(n) = sigma(sigma(n)-n), where sigma = A000203, sum of the divisors of n.

n	a(n)
2	1
3	1
4	4
5	1
6	12
7	1
8	8
9	7
10	15
11	1
12	31
13	1
14	18
15	13
16	24
17	1
18	32
19	1
20	36
21	12
22	24
23	1
24	91
25	12
26	31
27	14
28	56
29	1
30	96
31	1
32	32
33	24
34	42
35	14
36	72
37	1
38	36
39	18
40	93
41	1
42	120
43	1
44	90
45	48
46	42
47	1
48	140
49	15
50	44
51	32
52	72
53	1
54	144
55	18
56	127
57	24
58	63
59	1
60	280
61	1
62	54
63	42
64	104
65	20
66	168
67	1
68	90
69	40
70	114
71	1
72	168
73	1
74	90
75	57

[1, 1, 4, 1, 12, 1, 8, 7, 15, 1, 31, 1, 18, 13, 24, 1, 32, 1, 36, 12, 24, 1, 91, 12, 31, 14, 56, 1, 96, 1, 32, 24, 42, 14, 72, 1, 36, 18, 93, 1, 120, 1, 90, 48, 42, 1, 140, 15, 44, 32, 72, 1, 144, 18, 127, 24, 63, 1, 280, 1, 54, 42, 104, 20, 168, 1, 90, 40, 114, 1, 168, 1, 90, 57]

cp's OEIS Frontend

A072869 a(n) = sigma(sigma(n)-n), where sigma = A000203, sum of the divisors of n.

Table of values

List of values

n	a(n)
2	1
3	1
4	4
5	1
6	12
7	1
8	8
9	7
10	15
11	1
12	31
13	1
14	18
15	13
16	24
17	1
18	32
19	1
20	36
21	12
22	24
23	1
24	91
25	12
26	31
27	14
28	56
29	1
30	96
31	1
32	32
33	24
34	42
35	14
36	72
37	1
38	36
39	18
40	93
41	1
42	120
43	1
44	90
45	48
46	42
47	1
48	140
49	15
50	44
51	32
52	72
53	1
54	144
55	18
56	127
57	24
58	63
59	1
60	280
61	1
62	54
63	42
64	104
65	20
66	168
67	1
68	90
69	40
70	114
71	1
72	168
73	1
74	90
75	57

n	a(n)
2	1
3	1
4	4
5	1
6	12
7	1
8	8
9	7
10	15
11	1
12	31
13	1
14	18
15	13
16	24
17	1
18	32
19	1
20	36
21	12
22	24
23	1
24	91
25	12
26	31
27	14
28	56
29	1
30	96
31	1
32	32
33	24
34	42
35	14
36	72
37	1
38	36
39	18
40	93
41	1
42	120
43	1
44	90
45	48
46	42
47	1
48	140
49	15
50	44
51	32
52	72
53	1
54	144
55	18
56	127
57	24
58	63
59	1
60	280
61	1
62	54
63	42
64	104
65	20
66	168
67	1
68	90
69	40
70	114
71	1
72	168
73	1
74	90
75	57

n	a(n)
2	1
3	1
4	4
5	1
6	12
7	1
8	8
9	7
10	15
11	1
12	31
13	1
14	18
15	13
16	24
17	1
18	32
19	1
20	36
21	12
22	24
23	1
24	91
25	12
26	31
27	14
28	56
29	1
30	96
31	1
32	32
33	24
34	42
35	14
36	72
37	1
38	36
39	18
40	93
41	1
42	120
43	1
44	90
45	48
46	42
47	1
48	140
49	15
50	44
51	32
52	72
53	1
54	144
55	18
56	127
57	24
58	63
59	1
60	280
61	1
62	54
63	42
64	104
65	20
66	168
67	1
68	90
69	40
70	114
71	1
72	168
73	1
74	90
75	57