A316272 - cp's OEIS frontend

A316272 A fractal-like sequence: erasing all pairs of consecutive terms that include a prime and a composite number (in any order) leaves the sequence unchanged.

n	a(n)
1	1
2	2
3	3
4	4
5	1
6	6
7	5
8	2
9	3
10	7
11	8
12	4
13	1
14	6
15	9
16	11
17	5
18	2
19	3
20	7
21	13
22	10
23	8
24	4
25	1
26	6
27	9
28	12
29	17
30	11
31	5
32	2
33	3
34	7
35	13
36	19
37	14
38	10
39	8
40	4
41	1
42	6
43	9
44	12
45	15
46	23
47	17
48	11
49	5
50	2
51	3
52	7
53	13
54	19
55	29
56	16
57	14
58	10
59	8
60	4
61	1
62	6
63	9
64	12
65	15
66	18
67	31
68	23
69	17
70	11
71	5
72	2
73	3
74	7
75	13
76	19
77	29
78	37
79	20
80	16
81	14
82	10
83	8
84	4
85	1

[1, 2, 3, 4, 1, 6, 5, 2, 3, 7, 8, 4, 1, 6, 9, 11, 5, 2, 3, 7, 13, 10, 8, 4, 1, 6, 9, 12, 17, 11, 5, 2, 3, 7, 13, 19, 14, 10, 8, 4, 1, 6, 9, 12, 15, 23, 17, 11, 5, 2, 3, 7, 13, 19, 29, 16, 14, 10, 8, 4, 1, 6, 9, 12, 15, 18, 31, 23, 17, 11, 5, 2, 3, 7, 13, 19, 29, 37, 20, 16, 14, 10, 8, 4, 1]

cp's OEIS Frontend

A316272 A fractal-like sequence: erasing all pairs of consecutive terms that include a prime and a composite number (in any order) leaves the sequence unchanged.

Table of values

List of values

n	a(n)
1	1
2	2
3	3
4	4
5	1
6	6
7	5
8	2
9	3
10	7
11	8
12	4
13	1
14	6
15	9
16	11
17	5
18	2
19	3
20	7
21	13
22	10
23	8
24	4
25	1
26	6
27	9
28	12
29	17
30	11
31	5
32	2
33	3
34	7
35	13
36	19
37	14
38	10
39	8
40	4
41	1
42	6
43	9
44	12
45	15
46	23
47	17
48	11
49	5
50	2
51	3
52	7
53	13
54	19
55	29
56	16
57	14
58	10
59	8
60	4
61	1
62	6
63	9
64	12
65	15
66	18
67	31
68	23
69	17
70	11
71	5
72	2
73	3
74	7
75	13
76	19
77	29
78	37
79	20
80	16
81	14
82	10
83	8
84	4
85	1

n	a(n)
1	1
2	2
3	3
4	4
5	1
6	6
7	5
8	2
9	3
10	7
11	8
12	4
13	1
14	6
15	9
16	11
17	5
18	2
19	3
20	7
21	13
22	10
23	8
24	4
25	1
26	6
27	9
28	12
29	17
30	11
31	5
32	2
33	3
34	7
35	13
36	19
37	14
38	10
39	8
40	4
41	1
42	6
43	9
44	12
45	15
46	23
47	17
48	11
49	5
50	2
51	3
52	7
53	13
54	19
55	29
56	16
57	14
58	10
59	8
60	4
61	1
62	6
63	9
64	12
65	15
66	18
67	31
68	23
69	17
70	11
71	5
72	2
73	3
74	7
75	13
76	19
77	29
78	37
79	20
80	16
81	14
82	10
83	8
84	4
85	1

n	a(n)
1	1
2	2
3	3
4	4
5	1
6	6
7	5
8	2
9	3
10	7
11	8
12	4
13	1
14	6
15	9
16	11
17	5
18	2
19	3
20	7
21	13
22	10
23	8
24	4
25	1
26	6
27	9
28	12
29	17
30	11
31	5
32	2
33	3
34	7
35	13
36	19
37	14
38	10
39	8
40	4
41	1
42	6
43	9
44	12
45	15
46	23
47	17
48	11
49	5
50	2
51	3
52	7
53	13
54	19
55	29
56	16
57	14
58	10
59	8
60	4
61	1
62	6
63	9
64	12
65	15
66	18
67	31
68	23
69	17
70	11
71	5
72	2
73	3
74	7
75	13
76	19
77	29
78	37
79	20
80	16
81	14
82	10
83	8
84	4
85	1