A085817 - cp's OEIS frontend

A085817 Start at (2n+1)/4 and iterate the map x -> x*ceiling(x); sequence gives values of n for which the denominators in the orbit drop directly from 4 to 1, bypassing 2.

n	a(n)
1	4
2	6
3	7
4	9
5	12
6	13
7	14
8	15
9	20
10	21
11	22
12	23
13	24
14	30
15	31
16	36
17	38
18	39
19	41
20	44
21	45
22	46
23	47
24	52
25	53
26	54
27	55
28	56
29	62
30	63
31	69
32	70
33	71
34	73
35	76
36	77
37	78
38	79
39	81
40	86
41	87
42	88
43	94
44	95
45	96
46	97
47	101
48	102
49	103
50	105
51	108
52	109
53	110
54	111
55	112
56	118
57	119
58	120
59	126
60	127
61	129
62	132
63	133
64	134
65	135
66	137

[4, 6, 7, 9, 12, 13, 14, 15, 20, 21, 22, 23, 24, 30, 31, 36, 38, 39, 41, 44, 45, 46, 47, 52, 53, 54, 55, 56, 62, 63, 69, 70, 71, 73, 76, 77, 78, 79, 81, 86, 87, 88, 94, 95, 96, 97, 101, 102, 103, 105, 108, 109, 110, 111, 112, 118, 119, 120, 126, 127, 129, 132, 133, 134, 135, 137]

cp's OEIS Frontend

A085817 Start at (2n+1)/4 and iterate the map x -> x*ceiling(x); sequence gives values of n for which the denominators in the orbit drop directly from 4 to 1, bypassing 2.

Table of values

List of values

n	a(n)
1	4
2	6
3	7
4	9
5	12
6	13
7	14
8	15
9	20
10	21
11	22
12	23
13	24
14	30
15	31
16	36
17	38
18	39
19	41
20	44
21	45
22	46
23	47
24	52
25	53
26	54
27	55
28	56
29	62
30	63
31	69
32	70
33	71
34	73
35	76
36	77
37	78
38	79
39	81
40	86
41	87
42	88
43	94
44	95
45	96
46	97
47	101
48	102
49	103
50	105
51	108
52	109
53	110
54	111
55	112
56	118
57	119
58	120
59	126
60	127
61	129
62	132
63	133
64	134
65	135
66	137

n	a(n)
1	4
2	6
3	7
4	9
5	12
6	13
7	14
8	15
9	20
10	21
11	22
12	23
13	24
14	30
15	31
16	36
17	38
18	39
19	41
20	44
21	45
22	46
23	47
24	52
25	53
26	54
27	55
28	56
29	62
30	63
31	69
32	70
33	71
34	73
35	76
36	77
37	78
38	79
39	81
40	86
41	87
42	88
43	94
44	95
45	96
46	97
47	101
48	102
49	103
50	105
51	108
52	109
53	110
54	111
55	112
56	118
57	119
58	120
59	126
60	127
61	129
62	132
63	133
64	134
65	135
66	137

n	a(n)
1	4
2	6
3	7
4	9
5	12
6	13
7	14
8	15
9	20
10	21
11	22
12	23
13	24
14	30
15	31
16	36
17	38
18	39
19	41
20	44
21	45
22	46
23	47
24	52
25	53
26	54
27	55
28	56
29	62
30	63
31	69
32	70
33	71
34	73
35	76
36	77
37	78
38	79
39	81
40	86
41	87
42	88
43	94
44	95
45	96
46	97
47	101
48	102
49	103
50	105
51	108
52	109
53	110
54	111
55	112
56	118
57	119
58	120
59	126
60	127
61	129
62	132
63	133
64	134
65	135
66	137