A254077 - cp's OEIS frontend

A254077 a(n) = n if n <= 3, otherwise the smallest number not occurring earlier such that gcd(a(n),a(n-2)) > gcd(a(n),a(n-1)).

n	a(n)
1	1
2	2
3	3
4	4
5	6
6	8
7	9
8	10
9	12
10	5
11	14
12	15
13	7
14	18
15	21
16	16
17	27
18	20
19	33
20	24
21	11
22	26
23	22
24	13
25	28
26	39
27	32
28	30
29	44
30	25
31	34
32	35
33	17
34	40
35	51
36	36
37	68
38	42
39	52
40	45
41	38
42	48
43	19
44	46
45	57
46	23
47	54
48	69
49	50
50	63
51	55
52	49
53	60
54	56
55	65
56	58
57	70
58	29
59	62
60	87
61	31
62	66
63	93
64	64
65	75
66	72
67	85
68	74
69	80
70	37
71	76
72	111

[1, 2, 3, 4, 6, 8, 9, 10, 12, 5, 14, 15, 7, 18, 21, 16, 27, 20, 33, 24, 11, 26, 22, 13, 28, 39, 32, 30, 44, 25, 34, 35, 17, 40, 51, 36, 68, 42, 52, 45, 38, 48, 19, 46, 57, 23, 54, 69, 50, 63, 55, 49, 60, 56, 65, 58, 70, 29, 62, 87, 31, 66, 93, 64, 75, 72, 85, 74, 80, 37, 76, 111]

cp's OEIS Frontend

A254077 a(n) = n if n <= 3, otherwise the smallest number not occurring earlier such that gcd(a(n),a(n-2)) > gcd(a(n),a(n-1)).

Table of values

List of values

n	a(n)
1	1
2	2
3	3
4	4
5	6
6	8
7	9
8	10
9	12
10	5
11	14
12	15
13	7
14	18
15	21
16	16
17	27
18	20
19	33
20	24
21	11
22	26
23	22
24	13
25	28
26	39
27	32
28	30
29	44
30	25
31	34
32	35
33	17
34	40
35	51
36	36
37	68
38	42
39	52
40	45
41	38
42	48
43	19
44	46
45	57
46	23
47	54
48	69
49	50
50	63
51	55
52	49
53	60
54	56
55	65
56	58
57	70
58	29
59	62
60	87
61	31
62	66
63	93
64	64
65	75
66	72
67	85
68	74
69	80
70	37
71	76
72	111

n	a(n)
1	1
2	2
3	3
4	4
5	6
6	8
7	9
8	10
9	12
10	5
11	14
12	15
13	7
14	18
15	21
16	16
17	27
18	20
19	33
20	24
21	11
22	26
23	22
24	13
25	28
26	39
27	32
28	30
29	44
30	25
31	34
32	35
33	17
34	40
35	51
36	36
37	68
38	42
39	52
40	45
41	38
42	48
43	19
44	46
45	57
46	23
47	54
48	69
49	50
50	63
51	55
52	49
53	60
54	56
55	65
56	58
57	70
58	29
59	62
60	87
61	31
62	66
63	93
64	64
65	75
66	72
67	85
68	74
69	80
70	37
71	76
72	111

n	a(n)
1	1
2	2
3	3
4	4
5	6
6	8
7	9
8	10
9	12
10	5
11	14
12	15
13	7
14	18
15	21
16	16
17	27
18	20
19	33
20	24
21	11
22	26
23	22
24	13
25	28
26	39
27	32
28	30
29	44
30	25
31	34
32	35
33	17
34	40
35	51
36	36
37	68
38	42
39	52
40	45
41	38
42	48
43	19
44	46
45	57
46	23
47	54
48	69
49	50
50	63
51	55
52	49
53	60
54	56
55	65
56	58
57	70
58	29
59	62
60	87
61	31
62	66
63	93
64	64
65	75
66	72
67	85
68	74
69	80
70	37
71	76
72	111