A375889 - cp's OEIS frontend

A375889 a(1) = 1, a(2) = 3; for n > 2, a(n) is the smallest unused positive number such that a(n) shares a factor with a(n-1) and (a(n) AND a(n-1)) = min(a(n), a(n-1)), where AND is the binary AND operation.

n	a(n)
1	1
2	3
3	15
4	5
5	45
6	9
7	27
8	18
9	2
10	6
11	4
12	12
13	8
14	10
15	14
16	30
17	16
18	20
19	22
20	54
21	32
22	34
23	38
24	36
25	39
26	33
27	51
28	17
29	85
30	65
31	75
32	66
33	64
34	68
35	70
36	78
37	72
38	74
39	90
40	24
41	26
42	58
43	40
44	42
45	46
46	44
47	60
48	28
49	62
50	48
51	50
52	55
53	35
54	63
55	7
56	119
57	21
58	87
59	69
60	93
61	81
62	117
63	52
64	116
65	80
66	82
67	86
68	84
69	92
70	76
71	94
72	88
73	120
74	56
75	122
76	96

[1, 3, 15, 5, 45, 9, 27, 18, 2, 6, 4, 12, 8, 10, 14, 30, 16, 20, 22, 54, 32, 34, 38, 36, 39, 33, 51, 17, 85, 65, 75, 66, 64, 68, 70, 78, 72, 74, 90, 24, 26, 58, 40, 42, 46, 44, 60, 28, 62, 48, 50, 55, 35, 63, 7, 119, 21, 87, 69, 93, 81, 117, 52, 116, 80, 82, 86, 84, 92, 76, 94, 88, 120, 56, 122, 96]

cp's OEIS Frontend

A375889 a(1) = 1, a(2) = 3; for n > 2, a(n) is the smallest unused positive number such that a(n) shares a factor with a(n-1) and (a(n) AND a(n-1)) = min(a(n), a(n-1)), where AND is the binary AND operation.

Table of values

List of values

n	a(n)
1	1
2	3
3	15
4	5
5	45
6	9
7	27
8	18
9	2
10	6
11	4
12	12
13	8
14	10
15	14
16	30
17	16
18	20
19	22
20	54
21	32
22	34
23	38
24	36
25	39
26	33
27	51
28	17
29	85
30	65
31	75
32	66
33	64
34	68
35	70
36	78
37	72
38	74
39	90
40	24
41	26
42	58
43	40
44	42
45	46
46	44
47	60
48	28
49	62
50	48
51	50
52	55
53	35
54	63
55	7
56	119
57	21
58	87
59	69
60	93
61	81
62	117
63	52
64	116
65	80
66	82
67	86
68	84
69	92
70	76
71	94
72	88
73	120
74	56
75	122
76	96

n	a(n)
1	1
2	3
3	15
4	5
5	45
6	9
7	27
8	18
9	2
10	6
11	4
12	12
13	8
14	10
15	14
16	30
17	16
18	20
19	22
20	54
21	32
22	34
23	38
24	36
25	39
26	33
27	51
28	17
29	85
30	65
31	75
32	66
33	64
34	68
35	70
36	78
37	72
38	74
39	90
40	24
41	26
42	58
43	40
44	42
45	46
46	44
47	60
48	28
49	62
50	48
51	50
52	55
53	35
54	63
55	7
56	119
57	21
58	87
59	69
60	93
61	81
62	117
63	52
64	116
65	80
66	82
67	86
68	84
69	92
70	76
71	94
72	88
73	120
74	56
75	122
76	96

n	a(n)
1	1
2	3
3	15
4	5
5	45
6	9
7	27
8	18
9	2
10	6
11	4
12	12
13	8
14	10
15	14
16	30
17	16
18	20
19	22
20	54
21	32
22	34
23	38
24	36
25	39
26	33
27	51
28	17
29	85
30	65
31	75
32	66
33	64
34	68
35	70
36	78
37	72
38	74
39	90
40	24
41	26
42	58
43	40
44	42
45	46
46	44
47	60
48	28
49	62
50	48
51	50
52	55
53	35
54	63
55	7
56	119
57	21
58	87
59	69
60	93
61	81
62	117
63	52
64	116
65	80
66	82
67	86
68	84
69	92
70	76
71	94
72	88
73	120
74	56
75	122
76	96