A262373 - cp's OEIS frontend

A262373 a(1)=2, a(2)=5, a(3)=3; for n>3, a(n) is the smallest prime that has not already appeared and ends with the first digit in a(n-1) that equals 1, 3, 7 or 9.

n	a(n)
1	2
2	5
3	3
4	13
5	11
6	31
7	23
8	43
9	53
10	73
11	7
12	17
13	41
14	61
15	71
16	37
17	83
18	103
19	101
20	131
21	151
22	181
23	191
24	211
25	241
26	251
27	271
28	47
29	67
30	97
31	19
32	281
33	311
34	113
35	331
36	163
37	401
38	421
39	431
40	173
41	461
42	491
43	29
44	59
45	79
46	107
47	521
48	541
49	571
50	127
51	601
52	631
53	193
54	641
55	661
56	691
57	89
58	109

[2, 5, 3, 13, 11, 31, 23, 43, 53, 73, 7, 17, 41, 61, 71, 37, 83, 103, 101, 131, 151, 181, 191, 211, 241, 251, 271, 47, 67, 97, 19, 281, 311, 113, 331, 163, 401, 421, 431, 173, 461, 491, 29, 59, 79, 107, 521, 541, 571, 127, 601, 631, 193, 641, 661, 691, 89, 109]

cp's OEIS Frontend

A262373 a(1)=2, a(2)=5, a(3)=3; for n>3, a(n) is the smallest prime that has not already appeared and ends with the first digit in a(n-1) that equals 1, 3, 7 or 9.

Table of values

List of values

n	a(n)
1	2
2	5
3	3
4	13
5	11
6	31
7	23
8	43
9	53
10	73
11	7
12	17
13	41
14	61
15	71
16	37
17	83
18	103
19	101
20	131
21	151
22	181
23	191
24	211
25	241
26	251
27	271
28	47
29	67
30	97
31	19
32	281
33	311
34	113
35	331
36	163
37	401
38	421
39	431
40	173
41	461
42	491
43	29
44	59
45	79
46	107
47	521
48	541
49	571
50	127
51	601
52	631
53	193
54	641
55	661
56	691
57	89
58	109

n	a(n)
1	2
2	5
3	3
4	13
5	11
6	31
7	23
8	43
9	53
10	73
11	7
12	17
13	41
14	61
15	71
16	37
17	83
18	103
19	101
20	131
21	151
22	181
23	191
24	211
25	241
26	251
27	271
28	47
29	67
30	97
31	19
32	281
33	311
34	113
35	331
36	163
37	401
38	421
39	431
40	173
41	461
42	491
43	29
44	59
45	79
46	107
47	521
48	541
49	571
50	127
51	601
52	631
53	193
54	641
55	661
56	691
57	89
58	109

n	a(n)
1	2
2	5
3	3
4	13
5	11
6	31
7	23
8	43
9	53
10	73
11	7
12	17
13	41
14	61
15	71
16	37
17	83
18	103
19	101
20	131
21	151
22	181
23	191
24	211
25	241
26	251
27	271
28	47
29	67
30	97
31	19
32	281
33	311
34	113
35	331
36	163
37	401
38	421
39	431
40	173
41	461
42	491
43	29
44	59
45	79
46	107
47	521
48	541
49	571
50	127
51	601
52	631
53	193
54	641
55	661
56	691
57	89
58	109