A354720 - cp's OEIS frontend

A354720 a(n) = n for n <= 3; let i = a(n-2) and j = a(n-1); a(n+1) = least k not already in the sequence such that (j, k) = 1 and (i, k) = m > 1 and only one of either omega(i) or omega(k) exceed omega(m), where omega = A001221.

n	a(n)
1	1
2	2
3	3
4	10
5	21
6	4
7	7
8	6
9	35
10	8
11	5
12	12
13	55
14	9
15	11
16	15
17	22
18	25
19	16
20	45
21	14
22	27
23	32
24	33
25	20
26	81
27	64
28	39
29	28
30	13
31	42
32	65
33	18
34	125
35	66
36	85
37	24
38	17
39	30
40	119
41	36
42	49
43	60
44	77
45	40
46	121
47	70
48	99
49	50
50	231
51	128
52	63
53	26
54	105
55	169
56	75
57	52
58	165
59	182
60	135
61	56
62	195
63	154
64	117
65	44

[1, 2, 3, 10, 21, 4, 7, 6, 35, 8, 5, 12, 55, 9, 11, 15, 22, 25, 16, 45, 14, 27, 32, 33, 20, 81, 64, 39, 28, 13, 42, 65, 18, 125, 66, 85, 24, 17, 30, 119, 36, 49, 60, 77, 40, 121, 70, 99, 50, 231, 128, 63, 26, 105, 169, 75, 52, 165, 182, 135, 56, 195, 154, 117, 44]

cp's OEIS Frontend

A354720 a(n) = n for n <= 3; let i = a(n-2) and j = a(n-1); a(n+1) = least k not already in the sequence such that (j, k) = 1 and (i, k) = m > 1 and only one of either omega(i) or omega(k) exceed omega(m), where omega = A001221.

Table of values

List of values

n	a(n)
1	1
2	2
3	3
4	10
5	21
6	4
7	7
8	6
9	35
10	8
11	5
12	12
13	55
14	9
15	11
16	15
17	22
18	25
19	16
20	45
21	14
22	27
23	32
24	33
25	20
26	81
27	64
28	39
29	28
30	13
31	42
32	65
33	18
34	125
35	66
36	85
37	24
38	17
39	30
40	119
41	36
42	49
43	60
44	77
45	40
46	121
47	70
48	99
49	50
50	231
51	128
52	63
53	26
54	105
55	169
56	75
57	52
58	165
59	182
60	135
61	56
62	195
63	154
64	117
65	44

n	a(n)
1	1
2	2
3	3
4	10
5	21
6	4
7	7
8	6
9	35
10	8
11	5
12	12
13	55
14	9
15	11
16	15
17	22
18	25
19	16
20	45
21	14
22	27
23	32
24	33
25	20
26	81
27	64
28	39
29	28
30	13
31	42
32	65
33	18
34	125
35	66
36	85
37	24
38	17
39	30
40	119
41	36
42	49
43	60
44	77
45	40
46	121
47	70
48	99
49	50
50	231
51	128
52	63
53	26
54	105
55	169
56	75
57	52
58	165
59	182
60	135
61	56
62	195
63	154
64	117
65	44

n	a(n)
1	1
2	2
3	3
4	10
5	21
6	4
7	7
8	6
9	35
10	8
11	5
12	12
13	55
14	9
15	11
16	15
17	22
18	25
19	16
20	45
21	14
22	27
23	32
24	33
25	20
26	81
27	64
28	39
29	28
30	13
31	42
32	65
33	18
34	125
35	66
36	85
37	24
38	17
39	30
40	119
41	36
42	49
43	60
44	77
45	40
46	121
47	70
48	99
49	50
50	231
51	128
52	63
53	26
54	105
55	169
56	75
57	52
58	165
59	182
60	135
61	56
62	195
63	154
64	117
65	44