A121878 - cp's OEIS frontend

A121878 a(1)=1. a(n) = the smallest positive integer not occurring earlier in the sequence such that a(n-1)+a(n) is squarefree.

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

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

cp's OEIS Frontend

A121878 a(1)=1. a(n) = the smallest positive integer not occurring earlier in the sequence such that a(n-1)+a(n) is squarefree.

Table of values

List of values

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

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

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