A247942 - cp's OEIS frontend

A247942 a(n) = n if n <= 3, otherwise the smallest number not occurring earlier having at least one common factor with a(n-2)*a(n-3), but none with a(n-1).

n	a(n)
1	1
2	2
3	3
4	4
5	9
6	8
7	15
8	14
9	5
10	6
11	7
12	10
13	21
14	16
15	25
16	12
17	35
18	18
19	49
20	20
21	27
22	22
23	39
24	11
25	13
26	24
27	55
28	26
29	33
30	28
31	45
32	32
33	51
34	38
35	17
36	19
37	30
38	119
39	36
40	65
41	34
42	57
43	40
44	63
45	44
46	69
47	50
48	23
49	42
50	85
51	46
52	75
53	52
54	81
55	56
56	87
57	62
58	29
59	31
60	48

[1, 2, 3, 4, 9, 8, 15, 14, 5, 6, 7, 10, 21, 16, 25, 12, 35, 18, 49, 20, 27, 22, 39, 11, 13, 24, 55, 26, 33, 28, 45, 32, 51, 38, 17, 19, 30, 119, 36, 65, 34, 57, 40, 63, 44, 69, 50, 23, 42, 85, 46, 75, 52, 81, 56, 87, 62, 29, 31, 48]

cp's OEIS Frontend

A247942 a(n) = n if n <= 3, otherwise the smallest number not occurring earlier having at least one common factor with a(n-2)*a(n-3), but none with a(n-1).

Table of values

List of values

n	a(n)
1	1
2	2
3	3
4	4
5	9
6	8
7	15
8	14
9	5
10	6
11	7
12	10
13	21
14	16
15	25
16	12
17	35
18	18
19	49
20	20
21	27
22	22
23	39
24	11
25	13
26	24
27	55
28	26
29	33
30	28
31	45
32	32
33	51
34	38
35	17
36	19
37	30
38	119
39	36
40	65
41	34
42	57
43	40
44	63
45	44
46	69
47	50
48	23
49	42
50	85
51	46
52	75
53	52
54	81
55	56
56	87
57	62
58	29
59	31
60	48

n	a(n)
1	1
2	2
3	3
4	4
5	9
6	8
7	15
8	14
9	5
10	6
11	7
12	10
13	21
14	16
15	25
16	12
17	35
18	18
19	49
20	20
21	27
22	22
23	39
24	11
25	13
26	24
27	55
28	26
29	33
30	28
31	45
32	32
33	51
34	38
35	17
36	19
37	30
38	119
39	36
40	65
41	34
42	57
43	40
44	63
45	44
46	69
47	50
48	23
49	42
50	85
51	46
52	75
53	52
54	81
55	56
56	87
57	62
58	29
59	31
60	48

n	a(n)
1	1
2	2
3	3
4	4
5	9
6	8
7	15
8	14
9	5
10	6
11	7
12	10
13	21
14	16
15	25
16	12
17	35
18	18
19	49
20	20
21	27
22	22
23	39
24	11
25	13
26	24
27	55
28	26
29	33
30	28
31	45
32	32
33	51
34	38
35	17
36	19
37	30
38	119
39	36
40	65
41	34
42	57
43	40
44	63
45	44
46	69
47	50
48	23
49	42
50	85
51	46
52	75
53	52
54	81
55	56
56	87
57	62
58	29
59	31
60	48