A283156 - cp's OEIS frontend

A283156 Number of preimages of even integers under the sum-of-proper-divisors function.

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

[0, 1, 2, 2, 1, 1, 2, 2, 1, 2, 2, 1, 1, 1, 1, 2, 1, 1, 1, 3, 2, 2, 2, 1, 2, 0, 2, 1, 1, 1, 2, 3, 1, 1, 1, 1, 3, 3, 1, 1, 1, 1, 1, 0, 2, 2, 1, 0, 1, 2, 1, 2, 4, 2, 2, 1, 2, 1, 1, 0, 1, 0, 1, 1, 2, 1, 3, 2, 1, 3, 1, 1, 0, 2, 2, 2, 3, 2, 1, 1, 0, 1, 2, 1, 2, 1, 1]

cp's OEIS Frontend

A283156 Number of preimages of even integers under the sum-of-proper-divisors function.

Table of values

List of values

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

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

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