A378912 - cp's OEIS frontend

A378912 Irregular triangle read by rows: row n lists all positive m such that sigma(m) divides n, where sigma is the sum-of-divisors function (A000203).

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

[1, 1, 1, 2, 1, 3, 1, 1, 2, 5, 1, 4, 1, 3, 7, 1, 2, 1, 1, 1, 2, 3, 5, 6, 11, 1, 9, 1, 4, 13, 1, 2, 8, 1, 3, 7, 1, 1, 2, 5, 10, 17, 1, 1, 3, 19, 1, 2, 4, 1, 1, 1, 2, 3, 5, 6, 7, 11, 14, 15, 23, 1, 1, 9, 1, 2, 1, 3, 4, 12, 13, 1, 1, 2, 5, 8, 29, 1, 16, 25, 1, 3, 7, 21, 31]

cp's OEIS Frontend

A378912 Irregular triangle read by rows: row n lists all positive m such that sigma(m) divides n, where sigma is the sum-of-divisors function (A000203).

Table of values

List of values

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

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

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