A379441 - cp's OEIS frontend

A379441 a(1) = 1, a(2) = 2, for a(n) > 2, a(n) is the smallest unused positive number that shares a factor with a(n-1) such that the exponents of each distinct prime factor of a(n-1) differ by one from those of the same prime factors of a(n).

n	a(n)
1	1
2	2
3	4
4	6
5	9
6	3
7	18
8	12
9	8
10	16
11	24
12	20
13	14
14	36
15	30
16	25
17	5
18	50
19	15
20	63
21	27
22	45
23	21
24	49
25	7
26	98
27	28
28	10
29	44
30	26
31	60
32	22
33	52
34	34
35	76
36	40
37	48
38	32
39	64
40	96
41	80
42	56
43	68
44	38
45	84
46	46
47	100
48	70
49	75
50	35
51	147
52	77
53	121
54	11
55	242
56	33
57	72
58	108
59	90
60	39
61	99
62	42
63	92
64	54
65	81
66	135
67	117
68	51
69	126
70	57
71	144
72	120
73	112
74	88
75	116
76	62
77	132
78	58
79	124
80	66
81	140
82	74
83	156
84	82
85	148
86	78
87	153
88	69

[1, 2, 4, 6, 9, 3, 18, 12, 8, 16, 24, 20, 14, 36, 30, 25, 5, 50, 15, 63, 27, 45, 21, 49, 7, 98, 28, 10, 44, 26, 60, 22, 52, 34, 76, 40, 48, 32, 64, 96, 80, 56, 68, 38, 84, 46, 100, 70, 75, 35, 147, 77, 121, 11, 242, 33, 72, 108, 90, 39, 99, 42, 92, 54, 81, 135, 117, 51, 126, 57, 144, 120, 112, 88, 116, 62, 132, 58, 124, 66, 140, 74, 156, 82, 148, 78, 153, 69]

cp's OEIS Frontend

A379441 a(1) = 1, a(2) = 2, for a(n) > 2, a(n) is the smallest unused positive number that shares a factor with a(n-1) such that the exponents of each distinct prime factor of a(n-1) differ by one from those of the same prime factors of a(n).

Table of values

List of values

n	a(n)
1	1
2	2
3	4
4	6
5	9
6	3
7	18
8	12
9	8
10	16
11	24
12	20
13	14
14	36
15	30
16	25
17	5
18	50
19	15
20	63
21	27
22	45
23	21
24	49
25	7
26	98
27	28
28	10
29	44
30	26
31	60
32	22
33	52
34	34
35	76
36	40
37	48
38	32
39	64
40	96
41	80
42	56
43	68
44	38
45	84
46	46
47	100
48	70
49	75
50	35
51	147
52	77
53	121
54	11
55	242
56	33
57	72
58	108
59	90
60	39
61	99
62	42
63	92
64	54
65	81
66	135
67	117
68	51
69	126
70	57
71	144
72	120
73	112
74	88
75	116
76	62
77	132
78	58
79	124
80	66
81	140
82	74
83	156
84	82
85	148
86	78
87	153
88	69

n	a(n)
1	1
2	2
3	4
4	6
5	9
6	3
7	18
8	12
9	8
10	16
11	24
12	20
13	14
14	36
15	30
16	25
17	5
18	50
19	15
20	63
21	27
22	45
23	21
24	49
25	7
26	98
27	28
28	10
29	44
30	26
31	60
32	22
33	52
34	34
35	76
36	40
37	48
38	32
39	64
40	96
41	80
42	56
43	68
44	38
45	84
46	46
47	100
48	70
49	75
50	35
51	147
52	77
53	121
54	11
55	242
56	33
57	72
58	108
59	90
60	39
61	99
62	42
63	92
64	54
65	81
66	135
67	117
68	51
69	126
70	57
71	144
72	120
73	112
74	88
75	116
76	62
77	132
78	58
79	124
80	66
81	140
82	74
83	156
84	82
85	148
86	78
87	153
88	69

n	a(n)
1	1
2	2
3	4
4	6
5	9
6	3
7	18
8	12
9	8
10	16
11	24
12	20
13	14
14	36
15	30
16	25
17	5
18	50
19	15
20	63
21	27
22	45
23	21
24	49
25	7
26	98
27	28
28	10
29	44
30	26
31	60
32	22
33	52
34	34
35	76
36	40
37	48
38	32
39	64
40	96
41	80
42	56
43	68
44	38
45	84
46	46
47	100
48	70
49	75
50	35
51	147
52	77
53	121
54	11
55	242
56	33
57	72
58	108
59	90
60	39
61	99
62	42
63	92
64	54
65	81
66	135
67	117
68	51
69	126
70	57
71	144
72	120
73	112
74	88
75	116
76	62
77	132
78	58
79	124
80	66
81	140
82	74
83	156
84	82
85	148
86	78
87	153
88	69