A166133 - cp's OEIS frontend

A166133 After initial 1,2,4, a(n+1) is the smallest divisor of a(n)^2-1 that has not yet appeared in the sequence.

n	a(n)
1	1
2	2
3	4
4	3
5	8
6	7
7	6
8	5
9	12
10	11
11	10
12	9
13	16
14	15
15	14
16	13
17	21
18	20
19	19
20	18
21	17
22	24
23	23
24	22
25	69
26	28
27	27
28	26
29	25
30	39
31	38
32	37
33	36
34	35
35	34
36	33
37	32
38	31
39	30
40	29
41	40
42	41
43	42
44	43
45	44
46	45
47	46
48	47
49	48
50	49
51	50
52	51
53	52
54	53
55	54
56	55
57	56
58	57
59	58
60	59
61	60
62	61
63	62
64	63
65	64
66	65
67	66
68	67
69	68
70	201
71	80
72	79

[1, 2, 4, 3, 8, 7, 6, 5, 12, 11, 10, 9, 16, 15, 14, 13, 21, 20, 19, 18, 17, 24, 23, 22, 69, 28, 27, 26, 25, 39, 38, 37, 36, 35, 34, 33, 32, 31, 30, 29, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 201, 80, 79]

cp's OEIS Frontend

A166133 After initial 1,2,4, a(n+1) is the smallest divisor of a(n)^2-1 that has not yet appeared in the sequence.

Table of values

List of values

n	a(n)
1	1
2	2
3	4
4	3
5	8
6	7
7	6
8	5
9	12
10	11
11	10
12	9
13	16
14	15
15	14
16	13
17	21
18	20
19	19
20	18
21	17
22	24
23	23
24	22
25	69
26	28
27	27
28	26
29	25
30	39
31	38
32	37
33	36
34	35
35	34
36	33
37	32
38	31
39	30
40	29
41	40
42	41
43	42
44	43
45	44
46	45
47	46
48	47
49	48
50	49
51	50
52	51
53	52
54	53
55	54
56	55
57	56
58	57
59	58
60	59
61	60
62	61
63	62
64	63
65	64
66	65
67	66
68	67
69	68
70	201
71	80
72	79

n	a(n)
1	1
2	2
3	4
4	3
5	8
6	7
7	6
8	5
9	12
10	11
11	10
12	9
13	16
14	15
15	14
16	13
17	21
18	20
19	19
20	18
21	17
22	24
23	23
24	22
25	69
26	28
27	27
28	26
29	25
30	39
31	38
32	37
33	36
34	35
35	34
36	33
37	32
38	31
39	30
40	29
41	40
42	41
43	42
44	43
45	44
46	45
47	46
48	47
49	48
50	49
51	50
52	51
53	52
54	53
55	54
56	55
57	56
58	57
59	58
60	59
61	60
62	61
63	62
64	63
65	64
66	65
67	66
68	67
69	68
70	201
71	80
72	79

n	a(n)
1	1
2	2
3	4
4	3
5	8
6	7
7	6
8	5
9	12
10	11
11	10
12	9
13	16
14	15
15	14
16	13
17	21
18	20
19	19
20	18
21	17
22	24
23	23
24	22
25	69
26	28
27	27
28	26
29	25
30	39
31	38
32	37
33	36
34	35
35	34
36	33
37	32
38	31
39	30
40	29
41	40
42	41
43	42
44	43
45	44
46	45
47	46
48	47
49	48
50	49
51	50
52	51
53	52
54	53
55	54
56	55
57	56
58	57
59	58
60	59
61	60
62	61
63	62
64	63
65	64
66	65
67	66
68	67
69	68
70	201
71	80
72	79