A065496 - cp's OEIS frontend

A065496 Numbers n such that sigma(n) is a nontrivial power, i.e., sigma(n) = a^b where a and b are greater than 1.

n	a(n)
1	3
2	7
3	21
4	22
5	31
6	66
7	70
8	81
9	93
10	94
11	102
12	110
13	115
14	119
15	127
16	142
17	159
18	170
19	187
20	210
21	214
22	217
23	265
24	282
25	310
26	322
27	343
28	345
29	357
30	364
31	381
32	382
33	385
34	400
35	472
36	497
37	510
38	517
39	527
40	642
41	651
42	679
43	690
44	710
45	714
46	742
47	745
48	770
49	782
50	795
51	820
52	862
53	884
54	889

[3, 7, 21, 22, 31, 66, 70, 81, 93, 94, 102, 110, 115, 119, 127, 142, 159, 170, 187, 210, 214, 217, 265, 282, 310, 322, 343, 345, 357, 364, 381, 382, 385, 400, 472, 497, 510, 517, 527, 642, 651, 679, 690, 710, 714, 742, 745, 770, 782, 795, 820, 862, 884, 889]

cp's OEIS Frontend

A065496 Numbers n such that sigma(n) is a nontrivial power, i.e., sigma(n) = a^b where a and b are greater than 1.

Table of values

List of values

n	a(n)
1	3
2	7
3	21
4	22
5	31
6	66
7	70
8	81
9	93
10	94
11	102
12	110
13	115
14	119
15	127
16	142
17	159
18	170
19	187
20	210
21	214
22	217
23	265
24	282
25	310
26	322
27	343
28	345
29	357
30	364
31	381
32	382
33	385
34	400
35	472
36	497
37	510
38	517
39	527
40	642
41	651
42	679
43	690
44	710
45	714
46	742
47	745
48	770
49	782
50	795
51	820
52	862
53	884
54	889

n	a(n)
1	3
2	7
3	21
4	22
5	31
6	66
7	70
8	81
9	93
10	94
11	102
12	110
13	115
14	119
15	127
16	142
17	159
18	170
19	187
20	210
21	214
22	217
23	265
24	282
25	310
26	322
27	343
28	345
29	357
30	364
31	381
32	382
33	385
34	400
35	472
36	497
37	510
38	517
39	527
40	642
41	651
42	679
43	690
44	710
45	714
46	742
47	745
48	770
49	782
50	795
51	820
52	862
53	884
54	889

n	a(n)
1	3
2	7
3	21
4	22
5	31
6	66
7	70
8	81
9	93
10	94
11	102
12	110
13	115
14	119
15	127
16	142
17	159
18	170
19	187
20	210
21	214
22	217
23	265
24	282
25	310
26	322
27	343
28	345
29	357
30	364
31	381
32	382
33	385
34	400
35	472
36	497
37	510
38	517
39	527
40	642
41	651
42	679
43	690
44	710
45	714
46	742
47	745
48	770
49	782
50	795
51	820
52	862
53	884
54	889