A177958 - cp's OEIS frontend

A177958 a(n) = n for n <= 6; for n > 6, a(n) is the smallest number not already used such that gcd(a(n), a(n-1)) >= 6.

n	a(n)
1	1
2	2
3	3
4	4
5	5
6	6
7	12
8	18
9	9
10	27
11	36
12	24
13	8
14	16
15	32
16	40
17	10
18	20
19	30
20	15
21	45
22	54
23	42
24	7
25	14
26	21
27	28
28	35
29	49
30	56
31	48
32	60
33	50
34	25
35	75
36	90
37	63
38	70
39	77
40	11
41	22
42	33
43	44
44	55
45	66
46	72
47	64
48	80
49	88
50	96
51	78
52	13
53	26
54	39
55	52
56	65
57	91
58	84
59	98
60	105

[1, 2, 3, 4, 5, 6, 12, 18, 9, 27, 36, 24, 8, 16, 32, 40, 10, 20, 30, 15, 45, 54, 42, 7, 14, 21, 28, 35, 49, 56, 48, 60, 50, 25, 75, 90, 63, 70, 77, 11, 22, 33, 44, 55, 66, 72, 64, 80, 88, 96, 78, 13, 26, 39, 52, 65, 91, 84, 98, 105]

cp's OEIS Frontend

A177958 a(n) = n for n <= 6; for n > 6, a(n) is the smallest number not already used such that gcd(a(n), a(n-1)) >= 6.

Table of values

List of values

n	a(n)
1	1
2	2
3	3
4	4
5	5
6	6
7	12
8	18
9	9
10	27
11	36
12	24
13	8
14	16
15	32
16	40
17	10
18	20
19	30
20	15
21	45
22	54
23	42
24	7
25	14
26	21
27	28
28	35
29	49
30	56
31	48
32	60
33	50
34	25
35	75
36	90
37	63
38	70
39	77
40	11
41	22
42	33
43	44
44	55
45	66
46	72
47	64
48	80
49	88
50	96
51	78
52	13
53	26
54	39
55	52
56	65
57	91
58	84
59	98
60	105

n	a(n)
1	1
2	2
3	3
4	4
5	5
6	6
7	12
8	18
9	9
10	27
11	36
12	24
13	8
14	16
15	32
16	40
17	10
18	20
19	30
20	15
21	45
22	54
23	42
24	7
25	14
26	21
27	28
28	35
29	49
30	56
31	48
32	60
33	50
34	25
35	75
36	90
37	63
38	70
39	77
40	11
41	22
42	33
43	44
44	55
45	66
46	72
47	64
48	80
49	88
50	96
51	78
52	13
53	26
54	39
55	52
56	65
57	91
58	84
59	98
60	105

n	a(n)
1	1
2	2
3	3
4	4
5	5
6	6
7	12
8	18
9	9
10	27
11	36
12	24
13	8
14	16
15	32
16	40
17	10
18	20
19	30
20	15
21	45
22	54
23	42
24	7
25	14
26	21
27	28
28	35
29	49
30	56
31	48
32	60
33	50
34	25
35	75
36	90
37	63
38	70
39	77
40	11
41	22
42	33
43	44
44	55
45	66
46	72
47	64
48	80
49	88
50	96
51	78
52	13
53	26
54	39
55	52
56	65
57	91
58	84
59	98
60	105