A094044 - cp's OEIS frontend

A094044 Alternate prime and nonprime numbers not included earlier such that every concatenation of a pair of terms is a prime: a(2n) is nonprime and a(2n-1) is prime.

n	a(n)
1	2
2	9
3	7
4	1
5	3
6	49
7	19
8	33
9	13
10	21
11	11
12	51
13	47
14	87
15	31
16	63
17	17
18	77
19	23
20	39
21	29
22	27
23	41
24	57
25	37
26	69
27	59
28	81
29	61
30	99
31	67
32	91
33	73
34	93
35	43
36	117
37	79
38	111
39	71
40	119
41	53
42	129
43	83
44	177
45	89
46	123
47	113
48	143
49	107
50	171
51	103
52	141
53	97
54	159
55	157
56	133
57	109
58	121
59	139
60	169
61	151
62	153
63	137
64	147

[2, 9, 7, 1, 3, 49, 19, 33, 13, 21, 11, 51, 47, 87, 31, 63, 17, 77, 23, 39, 29, 27, 41, 57, 37, 69, 59, 81, 61, 99, 67, 91, 73, 93, 43, 117, 79, 111, 71, 119, 53, 129, 83, 177, 89, 123, 113, 143, 107, 171, 103, 141, 97, 159, 157, 133, 109, 121, 139, 169, 151, 153, 137, 147]

cp's OEIS Frontend

A094044 Alternate prime and nonprime numbers not included earlier such that every concatenation of a pair of terms is a prime: a(2n) is nonprime and a(2n-1) is prime.

Table of values

List of values

n	a(n)
1	2
2	9
3	7
4	1
5	3
6	49
7	19
8	33
9	13
10	21
11	11
12	51
13	47
14	87
15	31
16	63
17	17
18	77
19	23
20	39
21	29
22	27
23	41
24	57
25	37
26	69
27	59
28	81
29	61
30	99
31	67
32	91
33	73
34	93
35	43
36	117
37	79
38	111
39	71
40	119
41	53
42	129
43	83
44	177
45	89
46	123
47	113
48	143
49	107
50	171
51	103
52	141
53	97
54	159
55	157
56	133
57	109
58	121
59	139
60	169
61	151
62	153
63	137
64	147

n	a(n)
1	2
2	9
3	7
4	1
5	3
6	49
7	19
8	33
9	13
10	21
11	11
12	51
13	47
14	87
15	31
16	63
17	17
18	77
19	23
20	39
21	29
22	27
23	41
24	57
25	37
26	69
27	59
28	81
29	61
30	99
31	67
32	91
33	73
34	93
35	43
36	117
37	79
38	111
39	71
40	119
41	53
42	129
43	83
44	177
45	89
46	123
47	113
48	143
49	107
50	171
51	103
52	141
53	97
54	159
55	157
56	133
57	109
58	121
59	139
60	169
61	151
62	153
63	137
64	147

n	a(n)
1	2
2	9
3	7
4	1
5	3
6	49
7	19
8	33
9	13
10	21
11	11
12	51
13	47
14	87
15	31
16	63
17	17
18	77
19	23
20	39
21	29
22	27
23	41
24	57
25	37
26	69
27	59
28	81
29	61
30	99
31	67
32	91
33	73
34	93
35	43
36	117
37	79
38	111
39	71
40	119
41	53
42	129
43	83
44	177
45	89
46	123
47	113
48	143
49	107
50	171
51	103
52	141
53	97
54	159
55	157
56	133
57	109
58	121
59	139
60	169
61	151
62	153
63	137
64	147