A359973 - cp's OEIS frontend

A359973 Lexicographically earliest sequence of distinct positive integers such that for any n > 0, the concatenation of the decimal digits of n and a(n) or of a(n) and n yields a prime number.

n	a(n)
1	1
2	3
3	2
4	7
5	9
6	13
7	4
8	11
9	5
10	19
11	8
12	17
13	6
14	23
15	31
16	21
17	12
18	47
19	10
20	27
21	16
22	37
23	14
24	41
25	39
26	33
27	20
28	43
29	32
30	49
31	15
32	29
33	26
34	57
35	59
36	71
37	22
38	51
39	25
40	73
41	24
42	53
43	28
44	63
45	61
46	79
47	18
48	77
49	30
50	81
51	38
52	97
53	42
54	83
55	69
56	89
57	34
58	67
59	35
60	91
61	45
62	87
63	44
64	109
65	99
66	103
67	58

[1, 3, 2, 7, 9, 13, 4, 11, 5, 19, 8, 17, 6, 23, 31, 21, 12, 47, 10, 27, 16, 37, 14, 41, 39, 33, 20, 43, 32, 49, 15, 29, 26, 57, 59, 71, 22, 51, 25, 73, 24, 53, 28, 63, 61, 79, 18, 77, 30, 81, 38, 97, 42, 83, 69, 89, 34, 67, 35, 91, 45, 87, 44, 109, 99, 103, 58]

cp's OEIS Frontend

A359973 Lexicographically earliest sequence of distinct positive integers such that for any n > 0, the concatenation of the decimal digits of n and a(n) or of a(n) and n yields a prime number.

Table of values

List of values

n	a(n)
1	1
2	3
3	2
4	7
5	9
6	13
7	4
8	11
9	5
10	19
11	8
12	17
13	6
14	23
15	31
16	21
17	12
18	47
19	10
20	27
21	16
22	37
23	14
24	41
25	39
26	33
27	20
28	43
29	32
30	49
31	15
32	29
33	26
34	57
35	59
36	71
37	22
38	51
39	25
40	73
41	24
42	53
43	28
44	63
45	61
46	79
47	18
48	77
49	30
50	81
51	38
52	97
53	42
54	83
55	69
56	89
57	34
58	67
59	35
60	91
61	45
62	87
63	44
64	109
65	99
66	103
67	58

n	a(n)
1	1
2	3
3	2
4	7
5	9
6	13
7	4
8	11
9	5
10	19
11	8
12	17
13	6
14	23
15	31
16	21
17	12
18	47
19	10
20	27
21	16
22	37
23	14
24	41
25	39
26	33
27	20
28	43
29	32
30	49
31	15
32	29
33	26
34	57
35	59
36	71
37	22
38	51
39	25
40	73
41	24
42	53
43	28
44	63
45	61
46	79
47	18
48	77
49	30
50	81
51	38
52	97
53	42
54	83
55	69
56	89
57	34
58	67
59	35
60	91
61	45
62	87
63	44
64	109
65	99
66	103
67	58

n	a(n)
1	1
2	3
3	2
4	7
5	9
6	13
7	4
8	11
9	5
10	19
11	8
12	17
13	6
14	23
15	31
16	21
17	12
18	47
19	10
20	27
21	16
22	37
23	14
24	41
25	39
26	33
27	20
28	43
29	32
30	49
31	15
32	29
33	26
34	57
35	59
36	71
37	22
38	51
39	25
40	73
41	24
42	53
43	28
44	63
45	61
46	79
47	18
48	77
49	30
50	81
51	38
52	97
53	42
54	83
55	69
56	89
57	34
58	67
59	35
60	91
61	45
62	87
63	44
64	109
65	99
66	103
67	58