A257718 - cp's OEIS frontend

A257718 a(n) = smallest prime not included earlier such that a(n) + a(n-1) + a(n-2) is a prime and is of opposite index parity to a(n-1), beginning with a(1) = 3 and a(2) = 5.

n	a(n)
1	3
2	5
3	29
4	67
5	7
6	23
7	13
8	11
9	19
10	17
11	37
12	47
13	43
14	41
15	53
16	73
17	71
18	83
19	79
20	31
21	89
22	59
23	163
24	109
25	101
26	97
27	113
28	103
29	61
30	149
31	107
32	127
33	139
34	167
35	151
36	191
37	181
38	137
39	131
40	211
41	199
42	197
43	173
44	277
45	193
46	257
47	223
48	179
49	229
50	233
51	239
52	367
53	251
54	241
55	281
56	307
57	271
58	389
59	293
60	157

[3, 5, 29, 67, 7, 23, 13, 11, 19, 17, 37, 47, 43, 41, 53, 73, 71, 83, 79, 31, 89, 59, 163, 109, 101, 97, 113, 103, 61, 149, 107, 127, 139, 167, 151, 191, 181, 137, 131, 211, 199, 197, 173, 277, 193, 257, 223, 179, 229, 233, 239, 367, 251, 241, 281, 307, 271, 389, 293, 157]

cp's OEIS Frontend

A257718 a(n) = smallest prime not included earlier such that a(n) + a(n-1) + a(n-2) is a prime and is of opposite index parity to a(n-1), beginning with a(1) = 3 and a(2) = 5.

Table of values

List of values

n	a(n)
1	3
2	5
3	29
4	67
5	7
6	23
7	13
8	11
9	19
10	17
11	37
12	47
13	43
14	41
15	53
16	73
17	71
18	83
19	79
20	31
21	89
22	59
23	163
24	109
25	101
26	97
27	113
28	103
29	61
30	149
31	107
32	127
33	139
34	167
35	151
36	191
37	181
38	137
39	131
40	211
41	199
42	197
43	173
44	277
45	193
46	257
47	223
48	179
49	229
50	233
51	239
52	367
53	251
54	241
55	281
56	307
57	271
58	389
59	293
60	157

n	a(n)
1	3
2	5
3	29
4	67
5	7
6	23
7	13
8	11
9	19
10	17
11	37
12	47
13	43
14	41
15	53
16	73
17	71
18	83
19	79
20	31
21	89
22	59
23	163
24	109
25	101
26	97
27	113
28	103
29	61
30	149
31	107
32	127
33	139
34	167
35	151
36	191
37	181
38	137
39	131
40	211
41	199
42	197
43	173
44	277
45	193
46	257
47	223
48	179
49	229
50	233
51	239
52	367
53	251
54	241
55	281
56	307
57	271
58	389
59	293
60	157

n	a(n)
1	3
2	5
3	29
4	67
5	7
6	23
7	13
8	11
9	19
10	17
11	37
12	47
13	43
14	41
15	53
16	73
17	71
18	83
19	79
20	31
21	89
22	59
23	163
24	109
25	101
26	97
27	113
28	103
29	61
30	149
31	107
32	127
33	139
34	167
35	151
36	191
37	181
38	137
39	131
40	211
41	199
42	197
43	173
44	277
45	193
46	257
47	223
48	179
49	229
50	233
51	239
52	367
53	251
54	241
55	281
56	307
57	271
58	389
59	293
60	157