A175764 - cp's OEIS frontend

A175764 Number of iterations of the mapping k->f(k) to reach one of 2, 5, or 29, starting with k=n, and with f(k)=(k^2+4)/d, where d is the next-to-largest divisor of k^2+4, or -1 if the sequence never reaches one of the required values.

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

[1, 0, 9, 1, 0, 1, 2, 1, 1, 1, 1, 1, 8, 1, 2, 1, 4, 1, 1, 1, 1, 1, 9, 1, 5, 1, 3, 1, 0, 1, 1, 1, 3, 1, 2, 1, 6, 1, 1, 1, 1, 1, 5, 1, 2, 1, 10, 1, 1, 1, 1, 1, 1, 1, 9, 1, 10, 1, 1, 1, 1, 1, 1, 1, 2, 1, 6, 1, 1, 1, 1, 1, 10, 1, 9, 1, 5, 1, 1, 1, 1, 1, 2, 1, 2, 1, 6, 1, 1, 1, 1, 1, 5, 1, 2, 1, 3, 1, 1, 1, 1, 1, 11]

cp's OEIS Frontend

A175764 Number of iterations of the mapping k->f(k) to reach one of 2, 5, or 29, starting with k=n, and with f(k)=(k^2+4)/d, where d is the next-to-largest divisor of k^2+4, or -1 if the sequence never reaches one of the required values.

Table of values

List of values

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

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

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