A089566 - cp's OEIS frontend

A089566 a(1) = 11. For n > 1, a(n) is the least unused number such that every concatenation a(n)a(n-1)...a(2)a(1) is prime.

n	a(n)
1	11
2	2
3	4
4	3
5	5
6	9
7	1
8	30
9	6
10	20
11	16
12	8
13	24
14	15
15	13
16	39
17	36
18	56
19	64
20	72
21	29
22	49
23	27
24	60
25	54
26	63
27	65
28	45
29	12
30	99
31	28
32	47
33	88
34	51
35	83
36	31
37	59
38	94
39	336
40	108
41	182
42	204
43	184
44	38
45	37
46	188
47	210
48	91
49	62
50	10
51	224
52	202
53	128
54	115
55	66
56	111
57	156
58	566
59	43
60	255
61	279
62	315
63	180
64	257
65	102
66	118

[11, 2, 4, 3, 5, 9, 1, 30, 6, 20, 16, 8, 24, 15, 13, 39, 36, 56, 64, 72, 29, 49, 27, 60, 54, 63, 65, 45, 12, 99, 28, 47, 88, 51, 83, 31, 59, 94, 336, 108, 182, 204, 184, 38, 37, 188, 210, 91, 62, 10, 224, 202, 128, 115, 66, 111, 156, 566, 43, 255, 279, 315, 180, 257, 102, 118]

cp's OEIS Frontend

A089566 a(1) = 11. For n > 1, a(n) is the least unused number such that every concatenation a(n)a(n-1)...a(2)a(1) is prime.

Table of values

List of values

n	a(n)
1	11
2	2
3	4
4	3
5	5
6	9
7	1
8	30
9	6
10	20
11	16
12	8
13	24
14	15
15	13
16	39
17	36
18	56
19	64
20	72
21	29
22	49
23	27
24	60
25	54
26	63
27	65
28	45
29	12
30	99
31	28
32	47
33	88
34	51
35	83
36	31
37	59
38	94
39	336
40	108
41	182
42	204
43	184
44	38
45	37
46	188
47	210
48	91
49	62
50	10
51	224
52	202
53	128
54	115
55	66
56	111
57	156
58	566
59	43
60	255
61	279
62	315
63	180
64	257
65	102
66	118

n	a(n)
1	11
2	2
3	4
4	3
5	5
6	9
7	1
8	30
9	6
10	20
11	16
12	8
13	24
14	15
15	13
16	39
17	36
18	56
19	64
20	72
21	29
22	49
23	27
24	60
25	54
26	63
27	65
28	45
29	12
30	99
31	28
32	47
33	88
34	51
35	83
36	31
37	59
38	94
39	336
40	108
41	182
42	204
43	184
44	38
45	37
46	188
47	210
48	91
49	62
50	10
51	224
52	202
53	128
54	115
55	66
56	111
57	156
58	566
59	43
60	255
61	279
62	315
63	180
64	257
65	102
66	118

n	a(n)
1	11
2	2
3	4
4	3
5	5
6	9
7	1
8	30
9	6
10	20
11	16
12	8
13	24
14	15
15	13
16	39
17	36
18	56
19	64
20	72
21	29
22	49
23	27
24	60
25	54
26	63
27	65
28	45
29	12
30	99
31	28
32	47
33	88
34	51
35	83
36	31
37	59
38	94
39	336
40	108
41	182
42	204
43	184
44	38
45	37
46	188
47	210
48	91
49	62
50	10
51	224
52	202
53	128
54	115
55	66
56	111
57	156
58	566
59	43
60	255
61	279
62	315
63	180
64	257
65	102
66	118