A217559 - cp's OEIS frontend

A217559 Terms as well as ending/starting digits have alternating primality; this is the lexicographically earliest injective sequence with this property.

n	a(n)
1	1
2	2
3	4
4	3
5	6
6	5
7	8
8	7
9	9
10	23
11	10
12	29
13	22
14	11
15	24
16	31
17	25
18	13
19	12
20	17
21	14
22	37
23	15
24	19
25	26
26	53
27	16
28	59
29	28
30	71
31	30
32	73
33	18
34	79
35	20
36	211
37	21
38	223
39	48
40	227
41	49
42	229
43	27
44	41
45	32
46	43
47	44
48	233
49	45
50	47
51	46
52	239
53	33
54	61
55	34
56	241
57	35
58	67
59	60
60	251
61	36
62	257
63	62
64	83
65	63
66	89
67	38
68	263
69	64
70	269
71	39
72	271
73	50
74	277

[1, 2, 4, 3, 6, 5, 8, 7, 9, 23, 10, 29, 22, 11, 24, 31, 25, 13, 12, 17, 14, 37, 15, 19, 26, 53, 16, 59, 28, 71, 30, 73, 18, 79, 20, 211, 21, 223, 48, 227, 49, 229, 27, 41, 32, 43, 44, 233, 45, 47, 46, 239, 33, 61, 34, 241, 35, 67, 60, 251, 36, 257, 62, 83, 63, 89, 38, 263, 64, 269, 39, 271, 50, 277]

cp's OEIS Frontend

A217559 Terms as well as ending/starting digits have alternating primality; this is the lexicographically earliest injective sequence with this property.

Table of values

List of values

n	a(n)
1	1
2	2
3	4
4	3
5	6
6	5
7	8
8	7
9	9
10	23
11	10
12	29
13	22
14	11
15	24
16	31
17	25
18	13
19	12
20	17
21	14
22	37
23	15
24	19
25	26
26	53
27	16
28	59
29	28
30	71
31	30
32	73
33	18
34	79
35	20
36	211
37	21
38	223
39	48
40	227
41	49
42	229
43	27
44	41
45	32
46	43
47	44
48	233
49	45
50	47
51	46
52	239
53	33
54	61
55	34
56	241
57	35
58	67
59	60
60	251
61	36
62	257
63	62
64	83
65	63
66	89
67	38
68	263
69	64
70	269
71	39
72	271
73	50
74	277

n	a(n)
1	1
2	2
3	4
4	3
5	6
6	5
7	8
8	7
9	9
10	23
11	10
12	29
13	22
14	11
15	24
16	31
17	25
18	13
19	12
20	17
21	14
22	37
23	15
24	19
25	26
26	53
27	16
28	59
29	28
30	71
31	30
32	73
33	18
34	79
35	20
36	211
37	21
38	223
39	48
40	227
41	49
42	229
43	27
44	41
45	32
46	43
47	44
48	233
49	45
50	47
51	46
52	239
53	33
54	61
55	34
56	241
57	35
58	67
59	60
60	251
61	36
62	257
63	62
64	83
65	63
66	89
67	38
68	263
69	64
70	269
71	39
72	271
73	50
74	277

n	a(n)
1	1
2	2
3	4
4	3
5	6
6	5
7	8
8	7
9	9
10	23
11	10
12	29
13	22
14	11
15	24
16	31
17	25
18	13
19	12
20	17
21	14
22	37
23	15
24	19
25	26
26	53
27	16
28	59
29	28
30	71
31	30
32	73
33	18
34	79
35	20
36	211
37	21
38	223
39	48
40	227
41	49
42	229
43	27
44	41
45	32
46	43
47	44
48	233
49	45
50	47
51	46
52	239
53	33
54	61
55	34
56	241
57	35
58	67
59	60
60	251
61	36
62	257
63	62
64	83
65	63
66	89
67	38
68	263
69	64
70	269
71	39
72	271
73	50
74	277