A373357 - cp's OEIS frontend

A373357 a(1) = 1, a(2) = 2, a(3) = 15; for n > 3, a(n) is the smallest unused positive number that is coprime to a(n-1), shares a factor with a(n-2), while omega(a(n)) does not equal omega(a(n-1)) or omega(a(n-2)).

n	a(n)
1	1
2	2
3	15
4	154
5	3
6	10
7	231
8	4
9	21
10	110
11	7
12	6
13	385
14	8
15	33
16	70
17	9
18	14
19	165
20	16
21	35
22	66
23	5
24	12
25	455
26	27
27	20
28	273
29	25
30	18
31	595
32	32
33	45
34	182
35	81
36	22
37	105
38	11
39	24
40	715
41	64
42	39
43	140
44	13
45	28
46	195
47	49
48	26
49	315
50	128
51	51
52	130
53	17
54	36
55	935
56	243
57	34
58	285
59	256
60	55
61	42
62	121
63	38
64	429
65	19
66	44
67	399
68	512
69	57
70	170

[1, 2, 15, 154, 3, 10, 231, 4, 21, 110, 7, 6, 385, 8, 33, 70, 9, 14, 165, 16, 35, 66, 5, 12, 455, 27, 20, 273, 25, 18, 595, 32, 45, 182, 81, 22, 105, 11, 24, 715, 64, 39, 140, 13, 28, 195, 49, 26, 315, 128, 51, 130, 17, 36, 935, 243, 34, 285, 256, 55, 42, 121, 38, 429, 19, 44, 399, 512, 57, 170]

cp's OEIS Frontend

A373357 a(1) = 1, a(2) = 2, a(3) = 15; for n > 3, a(n) is the smallest unused positive number that is coprime to a(n-1), shares a factor with a(n-2), while omega(a(n)) does not equal omega(a(n-1)) or omega(a(n-2)).

Table of values

List of values

n	a(n)
1	1
2	2
3	15
4	154
5	3
6	10
7	231
8	4
9	21
10	110
11	7
12	6
13	385
14	8
15	33
16	70
17	9
18	14
19	165
20	16
21	35
22	66
23	5
24	12
25	455
26	27
27	20
28	273
29	25
30	18
31	595
32	32
33	45
34	182
35	81
36	22
37	105
38	11
39	24
40	715
41	64
42	39
43	140
44	13
45	28
46	195
47	49
48	26
49	315
50	128
51	51
52	130
53	17
54	36
55	935
56	243
57	34
58	285
59	256
60	55
61	42
62	121
63	38
64	429
65	19
66	44
67	399
68	512
69	57
70	170

n	a(n)
1	1
2	2
3	15
4	154
5	3
6	10
7	231
8	4
9	21
10	110
11	7
12	6
13	385
14	8
15	33
16	70
17	9
18	14
19	165
20	16
21	35
22	66
23	5
24	12
25	455
26	27
27	20
28	273
29	25
30	18
31	595
32	32
33	45
34	182
35	81
36	22
37	105
38	11
39	24
40	715
41	64
42	39
43	140
44	13
45	28
46	195
47	49
48	26
49	315
50	128
51	51
52	130
53	17
54	36
55	935
56	243
57	34
58	285
59	256
60	55
61	42
62	121
63	38
64	429
65	19
66	44
67	399
68	512
69	57
70	170

n	a(n)
1	1
2	2
3	15
4	154
5	3
6	10
7	231
8	4
9	21
10	110
11	7
12	6
13	385
14	8
15	33
16	70
17	9
18	14
19	165
20	16
21	35
22	66
23	5
24	12
25	455
26	27
27	20
28	273
29	25
30	18
31	595
32	32
33	45
34	182
35	81
36	22
37	105
38	11
39	24
40	715
41	64
42	39
43	140
44	13
45	28
46	195
47	49
48	26
49	315
50	128
51	51
52	130
53	17
54	36
55	935
56	243
57	34
58	285
59	256
60	55
61	42
62	121
63	38
64	429
65	19
66	44
67	399
68	512
69	57
70	170