A051444 - cp's OEIS frontend

A051444 Smallest k such that sigma(k) = n, or 0 if there is no such k, where sigma = A000203 = sum of divisors.

n	a(n)
1	1
2	0
3	2
4	3
5	0
6	5
7	4
8	7
9	0
10	0
11	0
12	6
13	9
14	13
15	8
16	0
17	0
18	10
19	0
20	19
21	0
22	0
23	0
24	14
25	0
26	0
27	0
28	12
29	0
30	29
31	16
32	21
33	0
34	0
35	0
36	22
37	0
38	37
39	18
40	27
41	0
42	20
43	0
44	43
45	0
46	0
47	0
48	33
49	0
50	0
51	0
52	0
53	0
54	34
55	0
56	28
57	49
58	0
59	0
60	24
61	0
62	61
63	32
64	0
65	0
66	0
67	0
68	67
69	0
70	0
71	0
72	30
73	0
74	73
75	0
76	0
77	0
78	45
79	0
80	57
81	0
82	0
83	0
84	44
85	0
86	0
87	0
88	0
89	0

[1, 0, 2, 3, 0, 5, 4, 7, 0, 0, 0, 6, 9, 13, 8, 0, 0, 10, 0, 19, 0, 0, 0, 14, 0, 0, 0, 12, 0, 29, 16, 21, 0, 0, 0, 22, 0, 37, 18, 27, 0, 20, 0, 43, 0, 0, 0, 33, 0, 0, 0, 0, 0, 34, 0, 28, 49, 0, 0, 24, 0, 61, 32, 0, 0, 0, 0, 67, 0, 0, 0, 30, 0, 73, 0, 0, 0, 45, 0, 57, 0, 0, 0, 44, 0, 0, 0, 0, 0]

cp's OEIS Frontend

A051444 Smallest k such that sigma(k) = n, or 0 if there is no such k, where sigma = A000203 = sum of divisors.

Table of values

List of values

n	a(n)
1	1
2	0
3	2
4	3
5	0
6	5
7	4
8	7
9	0
10	0
11	0
12	6
13	9
14	13
15	8
16	0
17	0
18	10
19	0
20	19
21	0
22	0
23	0
24	14
25	0
26	0
27	0
28	12
29	0
30	29
31	16
32	21
33	0
34	0
35	0
36	22
37	0
38	37
39	18
40	27
41	0
42	20
43	0
44	43
45	0
46	0
47	0
48	33
49	0
50	0
51	0
52	0
53	0
54	34
55	0
56	28
57	49
58	0
59	0
60	24
61	0
62	61
63	32
64	0
65	0
66	0
67	0
68	67
69	0
70	0
71	0
72	30
73	0
74	73
75	0
76	0
77	0
78	45
79	0
80	57
81	0
82	0
83	0
84	44
85	0
86	0
87	0
88	0
89	0

n	a(n)
1	1
2	0
3	2
4	3
5	0
6	5
7	4
8	7
9	0
10	0
11	0
12	6
13	9
14	13
15	8
16	0
17	0
18	10
19	0
20	19
21	0
22	0
23	0
24	14
25	0
26	0
27	0
28	12
29	0
30	29
31	16
32	21
33	0
34	0
35	0
36	22
37	0
38	37
39	18
40	27
41	0
42	20
43	0
44	43
45	0
46	0
47	0
48	33
49	0
50	0
51	0
52	0
53	0
54	34
55	0
56	28
57	49
58	0
59	0
60	24
61	0
62	61
63	32
64	0
65	0
66	0
67	0
68	67
69	0
70	0
71	0
72	30
73	0
74	73
75	0
76	0
77	0
78	45
79	0
80	57
81	0
82	0
83	0
84	44
85	0
86	0
87	0
88	0
89	0

n	a(n)
1	1
2	0
3	2
4	3
5	0
6	5
7	4
8	7
9	0
10	0
11	0
12	6
13	9
14	13
15	8
16	0
17	0
18	10
19	0
20	19
21	0
22	0
23	0
24	14
25	0
26	0
27	0
28	12
29	0
30	29
31	16
32	21
33	0
34	0
35	0
36	22
37	0
38	37
39	18
40	27
41	0
42	20
43	0
44	43
45	0
46	0
47	0
48	33
49	0
50	0
51	0
52	0
53	0
54	34
55	0
56	28
57	49
58	0
59	0
60	24
61	0
62	61
63	32
64	0
65	0
66	0
67	0
68	67
69	0
70	0
71	0
72	30
73	0
74	73
75	0
76	0
77	0
78	45
79	0
80	57
81	0
82	0
83	0
84	44
85	0
86	0
87	0
88	0
89	0