A291791 - cp's OEIS frontend

A291791 Numbers n whose trajectory under the iteration of k -> (sigma(k)+phi(k))/2 reaches a fraction.

n	a(n)
1	4
2	8
3	9
4	12
5	14
6	15
7	16
8	18
9	20
10	24
11	25
12	28
13	32
14	33
15	34
16	35
17	36
18	42
19	48
20	49
21	50
22	54
23	55
24	56
25	62
26	63
27	64
28	69
29	70
30	72
31	76
32	77
33	78
34	81
35	84
36	85
37	86
38	87
39	88
40	90
41	93
42	94
43	95
44	96
45	98
46	99
47	100
48	102
49	104
50	105
51	108
52	110
53	111

[4, 8, 9, 12, 14, 15, 16, 18, 20, 24, 25, 28, 32, 33, 34, 35, 36, 42, 48, 49, 50, 54, 55, 56, 62, 63, 64, 69, 70, 72, 76, 77, 78, 81, 84, 85, 86, 87, 88, 90, 93, 94, 95, 96, 98, 99, 100, 102, 104, 105, 108, 110, 111]

cp's OEIS Frontend

A291791 Numbers n whose trajectory under the iteration of k -> (sigma(k)+phi(k))/2 reaches a fraction.

Table of values

List of values

n	a(n)
1	4
2	8
3	9
4	12
5	14
6	15
7	16
8	18
9	20
10	24
11	25
12	28
13	32
14	33
15	34
16	35
17	36
18	42
19	48
20	49
21	50
22	54
23	55
24	56
25	62
26	63
27	64
28	69
29	70
30	72
31	76
32	77
33	78
34	81
35	84
36	85
37	86
38	87
39	88
40	90
41	93
42	94
43	95
44	96
45	98
46	99
47	100
48	102
49	104
50	105
51	108
52	110
53	111

n	a(n)
1	4
2	8
3	9
4	12
5	14
6	15
7	16
8	18
9	20
10	24
11	25
12	28
13	32
14	33
15	34
16	35
17	36
18	42
19	48
20	49
21	50
22	54
23	55
24	56
25	62
26	63
27	64
28	69
29	70
30	72
31	76
32	77
33	78
34	81
35	84
36	85
37	86
38	87
39	88
40	90
41	93
42	94
43	95
44	96
45	98
46	99
47	100
48	102
49	104
50	105
51	108
52	110
53	111

n	a(n)
1	4
2	8
3	9
4	12
5	14
6	15
7	16
8	18
9	20
10	24
11	25
12	28
13	32
14	33
15	34
16	35
17	36
18	42
19	48
20	49
21	50
22	54
23	55
24	56
25	62
26	63
27	64
28	69
29	70
30	72
31	76
32	77
33	78
34	81
35	84
36	85
37	86
38	87
39	88
40	90
41	93
42	94
43	95
44	96
45	98
46	99
47	100
48	102
49	104
50	105
51	108
52	110
53	111