A274718 - cp's OEIS frontend

A274718 Set x = n. Then a(n) is the number of iterations of successive applications of the map x = A001414(x) that leave x composite, or a(n) = -1 if x always remains composite.

n	a(n)
1	-1
2	0
3	0
4	-1
5	0
6	0
7	0
8	1
9	1
10	0
11	0
12	0
13	0
14	2
15	2
16	2
17	0
18	2
19	0
20	2
21	1
22	0
23	0
24	2
25	1
26	3
27	2
28	0
29	0
30	1
31	0
32	1
33	3
34	0
35	1
36	1
37	0
38	2
39	3
40	0
41	0
42	1
43	0
44	3
45	0
46	2
47	0
48	0
49	3
50	1
51	3
52	0
53	0
54	0
55	3
56	0
57	1
58	0
59	0
60	1
61	0
62	4
63	0
64	1
65	3
66	3
67	0
68	2
69	4
70	3
71	0
72	1
73	0
74	4
75	0
76	0
77	3
78	3
79	0
80	0
81	1
82	0
83	0
84	3
85	1
86	1
87	2
88	0
89	0
90	0
91	3
92	3
93	1
94	4
95	3
96	0
97	0
98	3
99	0
100	3
101	0
102	1
103	0
104	0
105	3

[-1, 0, 0, -1, 0, 0, 0, 1, 1, 0, 0, 0, 0, 2, 2, 2, 0, 2, 0, 2, 1, 0, 0, 2, 1, 3, 2, 0, 0, 1, 0, 1, 3, 0, 1, 1, 0, 2, 3, 0, 0, 1, 0, 3, 0, 2, 0, 0, 3, 1, 3, 0, 0, 0, 3, 0, 1, 0, 0, 1, 0, 4, 0, 1, 3, 3, 0, 2, 4, 3, 0, 1, 0, 4, 0, 0, 3, 3, 0, 0, 1, 0, 0, 3, 1, 1, 2, 0, 0, 0, 3, 3, 1, 4, 3, 0, 0, 3, 0, 3, 0, 1, 0, 0, 3]

cp's OEIS Frontend

A274718 Set x = n. Then a(n) is the number of iterations of successive applications of the map x = A001414(x) that leave x composite, or a(n) = -1 if x always remains composite.

Table of values

List of values

n	a(n)
1	-1
2	0
3	0
4	-1
5	0
6	0
7	0
8	1
9	1
10	0
11	0
12	0
13	0
14	2
15	2
16	2
17	0
18	2
19	0
20	2
21	1
22	0
23	0
24	2
25	1
26	3
27	2
28	0
29	0
30	1
31	0
32	1
33	3
34	0
35	1
36	1
37	0
38	2
39	3
40	0
41	0
42	1
43	0
44	3
45	0
46	2
47	0
48	0
49	3
50	1
51	3
52	0
53	0
54	0
55	3
56	0
57	1
58	0
59	0
60	1
61	0
62	4
63	0
64	1
65	3
66	3
67	0
68	2
69	4
70	3
71	0
72	1
73	0
74	4
75	0
76	0
77	3
78	3
79	0
80	0
81	1
82	0
83	0
84	3
85	1
86	1
87	2
88	0
89	0
90	0
91	3
92	3
93	1
94	4
95	3
96	0
97	0
98	3
99	0
100	3
101	0
102	1
103	0
104	0
105	3

n	a(n)
1	-1
2	0
3	0
4	-1
5	0
6	0
7	0
8	1
9	1
10	0
11	0
12	0
13	0
14	2
15	2
16	2
17	0
18	2
19	0
20	2
21	1
22	0
23	0
24	2
25	1
26	3
27	2
28	0
29	0
30	1
31	0
32	1
33	3
34	0
35	1
36	1
37	0
38	2
39	3
40	0
41	0
42	1
43	0
44	3
45	0
46	2
47	0
48	0
49	3
50	1
51	3
52	0
53	0
54	0
55	3
56	0
57	1
58	0
59	0
60	1
61	0
62	4
63	0
64	1
65	3
66	3
67	0
68	2
69	4
70	3
71	0
72	1
73	0
74	4
75	0
76	0
77	3
78	3
79	0
80	0
81	1
82	0
83	0
84	3
85	1
86	1
87	2
88	0
89	0
90	0
91	3
92	3
93	1
94	4
95	3
96	0
97	0
98	3
99	0
100	3
101	0
102	1
103	0
104	0
105	3

n	a(n)
1	-1
2	0
3	0
4	-1
5	0
6	0
7	0
8	1
9	1
10	0
11	0
12	0
13	0
14	2
15	2
16	2
17	0
18	2
19	0
20	2
21	1
22	0
23	0
24	2
25	1
26	3
27	2
28	0
29	0
30	1
31	0
32	1
33	3
34	0
35	1
36	1
37	0
38	2
39	3
40	0
41	0
42	1
43	0
44	3
45	0
46	2
47	0
48	0
49	3
50	1
51	3
52	0
53	0
54	0
55	3
56	0
57	1
58	0
59	0
60	1
61	0
62	4
63	0
64	1
65	3
66	3
67	0
68	2
69	4
70	3
71	0
72	1
73	0
74	4
75	0
76	0
77	3
78	3
79	0
80	0
81	1
82	0
83	0
84	3
85	1
86	1
87	2
88	0
89	0
90	0
91	3
92	3
93	1
94	4
95	3
96	0
97	0
98	3
99	0
100	3
101	0
102	1
103	0
104	0
105	3