A203620 - cp's OEIS frontend

A203620 A self-describing sequence: when the sequence is read as a string of digits, a(n) says the position of the digits that are prime.

n	a(n)
1	2
2	3
3	5
4	1
5	7
6	8
7	22
8	11
9	20
10	15
11	21
12	14
13	23
14	25
15	26
16	27
17	29
18	31
19	32
20	19
21	35
22	36
23	37
24	39
25	40
26	41
27	49
28	51
29	52
30	53
31	54
32	55
33	57
34	58
35	59
36	60
37	61
38	63
39	70
40	71
41	73
42	75
43	76
44	77
45	78
46	79
47	81
48	82
49	83
50	85
51	90
52	92
53	94
54	98
55	105
56	109
57	200
58	115
59	201
60	114
61	122
62	123
63	125
64	126

[2, 3, 5, 1, 7, 8, 22, 11, 20, 15, 21, 14, 23, 25, 26, 27, 29, 31, 32, 19, 35, 36, 37, 39, 40, 41, 49, 51, 52, 53, 54, 55, 57, 58, 59, 60, 61, 63, 70, 71, 73, 75, 76, 77, 78, 79, 81, 82, 83, 85, 90, 92, 94, 98, 105, 109, 200, 115, 201, 114, 122, 123, 125, 126]

cp's OEIS Frontend

A203620 A self-describing sequence: when the sequence is read as a string of digits, a(n) says the position of the digits that are prime.

Table of values

List of values

n	a(n)
1	2
2	3
3	5
4	1
5	7
6	8
7	22
8	11
9	20
10	15
11	21
12	14
13	23
14	25
15	26
16	27
17	29
18	31
19	32
20	19
21	35
22	36
23	37
24	39
25	40
26	41
27	49
28	51
29	52
30	53
31	54
32	55
33	57
34	58
35	59
36	60
37	61
38	63
39	70
40	71
41	73
42	75
43	76
44	77
45	78
46	79
47	81
48	82
49	83
50	85
51	90
52	92
53	94
54	98
55	105
56	109
57	200
58	115
59	201
60	114
61	122
62	123
63	125
64	126

n	a(n)
1	2
2	3
3	5
4	1
5	7
6	8
7	22
8	11
9	20
10	15
11	21
12	14
13	23
14	25
15	26
16	27
17	29
18	31
19	32
20	19
21	35
22	36
23	37
24	39
25	40
26	41
27	49
28	51
29	52
30	53
31	54
32	55
33	57
34	58
35	59
36	60
37	61
38	63
39	70
40	71
41	73
42	75
43	76
44	77
45	78
46	79
47	81
48	82
49	83
50	85
51	90
52	92
53	94
54	98
55	105
56	109
57	200
58	115
59	201
60	114
61	122
62	123
63	125
64	126

n	a(n)
1	2
2	3
3	5
4	1
5	7
6	8
7	22
8	11
9	20
10	15
11	21
12	14
13	23
14	25
15	26
16	27
17	29
18	31
19	32
20	19
21	35
22	36
23	37
24	39
25	40
26	41
27	49
28	51
29	52
30	53
31	54
32	55
33	57
34	58
35	59
36	60
37	61
38	63
39	70
40	71
41	73
42	75
43	76
44	77
45	78
46	79
47	81
48	82
49	83
50	85
51	90
52	92
53	94
54	98
55	105
56	109
57	200
58	115
59	201
60	114
61	122
62	123
63	125
64	126