A256224 - cp's OEIS frontend

A256224 a(n) = n if n <= 3, otherwise a(n) is the smallest number not occurring earlier such that gcd(a(n-2), a(n)) is a prime or a power of a prime (but not 1) and gcd(a(n-1), a(n))=1.

n	a(n)
1	1
2	2
3	3
4	4
5	9
6	8
7	15
8	14
9	5
10	6
11	25
12	16
13	35
14	12
15	7
16	10
17	21
18	22
19	27
20	11
21	18
22	55
23	26
24	33
25	13
26	24
27	65
28	28
29	39
30	20
31	51
32	32
33	17
34	30
35	119
36	38
37	49
38	19
39	42
40	95
41	34
42	45
43	44
44	57
45	40
46	63
47	46
48	75
49	23
50	36
51	115
52	52
53	69
54	50
55	81
56	56
57	87
58	62
59	29
60	31
61	58
62	93
63	64
64	99
65	68
66	77
67	48

[1, 2, 3, 4, 9, 8, 15, 14, 5, 6, 25, 16, 35, 12, 7, 10, 21, 22, 27, 11, 18, 55, 26, 33, 13, 24, 65, 28, 39, 20, 51, 32, 17, 30, 119, 38, 49, 19, 42, 95, 34, 45, 44, 57, 40, 63, 46, 75, 23, 36, 115, 52, 69, 50, 81, 56, 87, 62, 29, 31, 58, 93, 64, 99, 68, 77, 48]

cp's OEIS Frontend

A256224 a(n) = n if n <= 3, otherwise a(n) is the smallest number not occurring earlier such that gcd(a(n-2), a(n)) is a prime or a power of a prime (but not 1) and gcd(a(n-1), a(n))=1.

Table of values

List of values

n	a(n)
1	1
2	2
3	3
4	4
5	9
6	8
7	15
8	14
9	5
10	6
11	25
12	16
13	35
14	12
15	7
16	10
17	21
18	22
19	27
20	11
21	18
22	55
23	26
24	33
25	13
26	24
27	65
28	28
29	39
30	20
31	51
32	32
33	17
34	30
35	119
36	38
37	49
38	19
39	42
40	95
41	34
42	45
43	44
44	57
45	40
46	63
47	46
48	75
49	23
50	36
51	115
52	52
53	69
54	50
55	81
56	56
57	87
58	62
59	29
60	31
61	58
62	93
63	64
64	99
65	68
66	77
67	48

n	a(n)
1	1
2	2
3	3
4	4
5	9
6	8
7	15
8	14
9	5
10	6
11	25
12	16
13	35
14	12
15	7
16	10
17	21
18	22
19	27
20	11
21	18
22	55
23	26
24	33
25	13
26	24
27	65
28	28
29	39
30	20
31	51
32	32
33	17
34	30
35	119
36	38
37	49
38	19
39	42
40	95
41	34
42	45
43	44
44	57
45	40
46	63
47	46
48	75
49	23
50	36
51	115
52	52
53	69
54	50
55	81
56	56
57	87
58	62
59	29
60	31
61	58
62	93
63	64
64	99
65	68
66	77
67	48

n	a(n)
1	1
2	2
3	3
4	4
5	9
6	8
7	15
8	14
9	5
10	6
11	25
12	16
13	35
14	12
15	7
16	10
17	21
18	22
19	27
20	11
21	18
22	55
23	26
24	33
25	13
26	24
27	65
28	28
29	39
30	20
31	51
32	32
33	17
34	30
35	119
36	38
37	49
38	19
39	42
40	95
41	34
42	45
43	44
44	57
45	40
46	63
47	46
48	75
49	23
50	36
51	115
52	52
53	69
54	50
55	81
56	56
57	87
58	62
59	29
60	31
61	58
62	93
63	64
64	99
65	68
66	77
67	48