A213320 - cp's OEIS frontend

A213320 Numbers such that the number of nonprime substrings equals the number of digits (substrings with leading zeros are considered to be nonprime).

n	a(n)
1	1
2	4
3	6
4	8
5	9
6	11
7	12
8	15
9	19
10	20
11	21
12	24
13	26
14	28
15	30
16	34
17	36
18	38
19	39
20	41
21	42
22	45
23	50
24	51
25	54
26	56
27	58
28	61
29	62
30	63
31	65
32	70
33	74
34	76
35	78
36	82
37	85
38	87
39	89
40	92
41	93
42	95
43	117
44	123
45	127
46	132
47	133
48	135
49	139
50	153
51	157
52	167
53	171
54	172
55	175

[1, 4, 6, 8, 9, 11, 12, 15, 19, 20, 21, 24, 26, 28, 30, 34, 36, 38, 39, 41, 42, 45, 50, 51, 54, 56, 58, 61, 62, 63, 65, 70, 74, 76, 78, 82, 85, 87, 89, 92, 93, 95, 117, 123, 127, 132, 133, 135, 139, 153, 157, 167, 171, 172, 175]

cp's OEIS Frontend

A213320 Numbers such that the number of nonprime substrings equals the number of digits (substrings with leading zeros are considered to be nonprime).

Table of values

List of values

n	a(n)
1	1
2	4
3	6
4	8
5	9
6	11
7	12
8	15
9	19
10	20
11	21
12	24
13	26
14	28
15	30
16	34
17	36
18	38
19	39
20	41
21	42
22	45
23	50
24	51
25	54
26	56
27	58
28	61
29	62
30	63
31	65
32	70
33	74
34	76
35	78
36	82
37	85
38	87
39	89
40	92
41	93
42	95
43	117
44	123
45	127
46	132
47	133
48	135
49	139
50	153
51	157
52	167
53	171
54	172
55	175

n	a(n)
1	1
2	4
3	6
4	8
5	9
6	11
7	12
8	15
9	19
10	20
11	21
12	24
13	26
14	28
15	30
16	34
17	36
18	38
19	39
20	41
21	42
22	45
23	50
24	51
25	54
26	56
27	58
28	61
29	62
30	63
31	65
32	70
33	74
34	76
35	78
36	82
37	85
38	87
39	89
40	92
41	93
42	95
43	117
44	123
45	127
46	132
47	133
48	135
49	139
50	153
51	157
52	167
53	171
54	172
55	175

n	a(n)
1	1
2	4
3	6
4	8
5	9
6	11
7	12
8	15
9	19
10	20
11	21
12	24
13	26
14	28
15	30
16	34
17	36
18	38
19	39
20	41
21	42
22	45
23	50
24	51
25	54
26	56
27	58
28	61
29	62
30	63
31	65
32	70
33	74
34	76
35	78
36	82
37	85
38	87
39	89
40	92
41	93
42	95
43	117
44	123
45	127
46	132
47	133
48	135
49	139
50	153
51	157
52	167
53	171
54	172
55	175