A091569 - cp's OEIS frontend

A091569 a(1) = 1; for n > 1, a(n) is the smallest positive integer not already used such that a(n)*a(n-1) + 1 is a perfect square.

n	a(n)
1	1
2	3
3	5
4	7
5	9
6	11
7	13
8	15
9	8
10	6
11	4
12	2
13	12
14	10
15	36
16	34
17	32
18	30
19	28
20	26
21	24
22	22
23	20
24	18
25	16
26	14
27	52
28	50
29	48
30	35
31	33
32	31
33	29
34	27
35	25
36	23
37	21
38	19
39	17
40	64
41	62
42	60
43	40
44	38
45	148
46	146
47	144
48	37
49	39
50	41
51	43
52	45
53	47
54	49
55	51
56	53
57	55
58	57
59	59
60	61
61	63
62	65
63	67
64	69
65	71
66	73
67	75
68	77
69	79
70	81
71	83

[1, 3, 5, 7, 9, 11, 13, 15, 8, 6, 4, 2, 12, 10, 36, 34, 32, 30, 28, 26, 24, 22, 20, 18, 16, 14, 52, 50, 48, 35, 33, 31, 29, 27, 25, 23, 21, 19, 17, 64, 62, 60, 40, 38, 148, 146, 144, 37, 39, 41, 43, 45, 47, 49, 51, 53, 55, 57, 59, 61, 63, 65, 67, 69, 71, 73, 75, 77, 79, 81, 83]

cp's OEIS Frontend

A091569 a(1) = 1; for n > 1, a(n) is the smallest positive integer not already used such that a(n)*a(n-1) + 1 is a perfect square.

Table of values

List of values

n	a(n)
1	1
2	3
3	5
4	7
5	9
6	11
7	13
8	15
9	8
10	6
11	4
12	2
13	12
14	10
15	36
16	34
17	32
18	30
19	28
20	26
21	24
22	22
23	20
24	18
25	16
26	14
27	52
28	50
29	48
30	35
31	33
32	31
33	29
34	27
35	25
36	23
37	21
38	19
39	17
40	64
41	62
42	60
43	40
44	38
45	148
46	146
47	144
48	37
49	39
50	41
51	43
52	45
53	47
54	49
55	51
56	53
57	55
58	57
59	59
60	61
61	63
62	65
63	67
64	69
65	71
66	73
67	75
68	77
69	79
70	81
71	83

n	a(n)
1	1
2	3
3	5
4	7
5	9
6	11
7	13
8	15
9	8
10	6
11	4
12	2
13	12
14	10
15	36
16	34
17	32
18	30
19	28
20	26
21	24
22	22
23	20
24	18
25	16
26	14
27	52
28	50
29	48
30	35
31	33
32	31
33	29
34	27
35	25
36	23
37	21
38	19
39	17
40	64
41	62
42	60
43	40
44	38
45	148
46	146
47	144
48	37
49	39
50	41
51	43
52	45
53	47
54	49
55	51
56	53
57	55
58	57
59	59
60	61
61	63
62	65
63	67
64	69
65	71
66	73
67	75
68	77
69	79
70	81
71	83

n	a(n)
1	1
2	3
3	5
4	7
5	9
6	11
7	13
8	15
9	8
10	6
11	4
12	2
13	12
14	10
15	36
16	34
17	32
18	30
19	28
20	26
21	24
22	22
23	20
24	18
25	16
26	14
27	52
28	50
29	48
30	35
31	33
32	31
33	29
34	27
35	25
36	23
37	21
38	19
39	17
40	64
41	62
42	60
43	40
44	38
45	148
46	146
47	144
48	37
49	39
50	41
51	43
52	45
53	47
54	49
55	51
56	53
57	55
58	57
59	59
60	61
61	63
62	65
63	67
64	69
65	71
66	73
67	75
68	77
69	79
70	81
71	83