A216781 - cp's OEIS frontend

A216781 Numbers such that numerator(sigma(n)/n) is odd and denominator(sigma(n)/n) is even.

n	a(n)
1	2
2	4
3	8
4	16
5	18
6	20
7	24
8	32
9	36
10	40
11	48
12	50
13	52
14	64
15	68
16	72
17	80
18	88
19	96
20	98
21	100
22	104
23	112
24	116
25	128
26	136
27	144
28	148
29	152
30	160
31	162
32	164
33	176
34	180
35	192
36	196
37	200
38	208
39	212
40	224
41	232
42	240
43	242
44	244
45	256
46	272
47	288
48	292
49	296
50	304
51	320
52	324
53	328
54	338
55	344
56	352

[2, 4, 8, 16, 18, 20, 24, 32, 36, 40, 48, 50, 52, 64, 68, 72, 80, 88, 96, 98, 100, 104, 112, 116, 128, 136, 144, 148, 152, 160, 162, 164, 176, 180, 192, 196, 200, 208, 212, 224, 232, 240, 242, 244, 256, 272, 288, 292, 296, 304, 320, 324, 328, 338, 344, 352]

cp's OEIS Frontend

A216781 Numbers such that numerator(sigma(n)/n) is odd and denominator(sigma(n)/n) is even.

Table of values

List of values

n	a(n)
1	2
2	4
3	8
4	16
5	18
6	20
7	24
8	32
9	36
10	40
11	48
12	50
13	52
14	64
15	68
16	72
17	80
18	88
19	96
20	98
21	100
22	104
23	112
24	116
25	128
26	136
27	144
28	148
29	152
30	160
31	162
32	164
33	176
34	180
35	192
36	196
37	200
38	208
39	212
40	224
41	232
42	240
43	242
44	244
45	256
46	272
47	288
48	292
49	296
50	304
51	320
52	324
53	328
54	338
55	344
56	352

n	a(n)
1	2
2	4
3	8
4	16
5	18
6	20
7	24
8	32
9	36
10	40
11	48
12	50
13	52
14	64
15	68
16	72
17	80
18	88
19	96
20	98
21	100
22	104
23	112
24	116
25	128
26	136
27	144
28	148
29	152
30	160
31	162
32	164
33	176
34	180
35	192
36	196
37	200
38	208
39	212
40	224
41	232
42	240
43	242
44	244
45	256
46	272
47	288
48	292
49	296
50	304
51	320
52	324
53	328
54	338
55	344
56	352

n	a(n)
1	2
2	4
3	8
4	16
5	18
6	20
7	24
8	32
9	36
10	40
11	48
12	50
13	52
14	64
15	68
16	72
17	80
18	88
19	96
20	98
21	100
22	104
23	112
24	116
25	128
26	136
27	144
28	148
29	152
30	160
31	162
32	164
33	176
34	180
35	192
36	196
37	200
38	208
39	212
40	224
41	232
42	240
43	242
44	244
45	256
46	272
47	288
48	292
49	296
50	304
51	320
52	324
53	328
54	338
55	344
56	352