A100113 - cp's OEIS frontend

A100113 a(n) = n if n <= 2, otherwise (smallest squarefree number m not occurring earlier such that gcd(m, a(n-1)) > 1).

n	a(n)
1	1
2	2
3	6
4	3
5	15
6	5
7	10
8	14
9	7
10	21
11	30
12	22
13	11
14	33
15	39
16	13
17	26
18	34
19	17
20	51
21	42
22	35
23	55
24	65
25	70
26	38
27	19
28	57
29	66
30	46
31	23
32	69
33	78
34	58
35	29
36	87
37	93
38	31
39	62
40	74
41	37
42	111
43	102
44	82
45	41
46	123
47	105
48	77
49	91
50	119
51	85
52	95
53	110
54	86
55	43
56	129
57	114
58	94
59	47
60	141
61	138
62	106
63	53
64	159
65	165
66	115
67	130

[1, 2, 6, 3, 15, 5, 10, 14, 7, 21, 30, 22, 11, 33, 39, 13, 26, 34, 17, 51, 42, 35, 55, 65, 70, 38, 19, 57, 66, 46, 23, 69, 78, 58, 29, 87, 93, 31, 62, 74, 37, 111, 102, 82, 41, 123, 105, 77, 91, 119, 85, 95, 110, 86, 43, 129, 114, 94, 47, 141, 138, 106, 53, 159, 165, 115, 130]

cp's OEIS Frontend

A100113 a(n) = n if n <= 2, otherwise (smallest squarefree number m not occurring earlier such that gcd(m, a(n-1)) > 1).

Table of values

List of values

n	a(n)
1	1
2	2
3	6
4	3
5	15
6	5
7	10
8	14
9	7
10	21
11	30
12	22
13	11
14	33
15	39
16	13
17	26
18	34
19	17
20	51
21	42
22	35
23	55
24	65
25	70
26	38
27	19
28	57
29	66
30	46
31	23
32	69
33	78
34	58
35	29
36	87
37	93
38	31
39	62
40	74
41	37
42	111
43	102
44	82
45	41
46	123
47	105
48	77
49	91
50	119
51	85
52	95
53	110
54	86
55	43
56	129
57	114
58	94
59	47
60	141
61	138
62	106
63	53
64	159
65	165
66	115
67	130

n	a(n)
1	1
2	2
3	6
4	3
5	15
6	5
7	10
8	14
9	7
10	21
11	30
12	22
13	11
14	33
15	39
16	13
17	26
18	34
19	17
20	51
21	42
22	35
23	55
24	65
25	70
26	38
27	19
28	57
29	66
30	46
31	23
32	69
33	78
34	58
35	29
36	87
37	93
38	31
39	62
40	74
41	37
42	111
43	102
44	82
45	41
46	123
47	105
48	77
49	91
50	119
51	85
52	95
53	110
54	86
55	43
56	129
57	114
58	94
59	47
60	141
61	138
62	106
63	53
64	159
65	165
66	115
67	130

n	a(n)
1	1
2	2
3	6
4	3
5	15
6	5
7	10
8	14
9	7
10	21
11	30
12	22
13	11
14	33
15	39
16	13
17	26
18	34
19	17
20	51
21	42
22	35
23	55
24	65
25	70
26	38
27	19
28	57
29	66
30	46
31	23
32	69
33	78
34	58
35	29
36	87
37	93
38	31
39	62
40	74
41	37
42	111
43	102
44	82
45	41
46	123
47	105
48	77
49	91
50	119
51	85
52	95
53	110
54	86
55	43
56	129
57	114
58	94
59	47
60	141
61	138
62	106
63	53
64	159
65	165
66	115
67	130