A272895 - cp's OEIS frontend

A272895 a(n) is the largest natural number k such that the composite number (2n+1) 2^k+1 has a nontrivial divisor of the form h2^s+1 (h odd) with 2s>k. If such a natural number does not exist, we set a(n)=0.

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

[0, 3, 4, 5, 5, 2, 6, 7, 6, 4, 3, 4, 7, 1, 8, 9, 8, 6, 3, 4, 6, 5, 1, 6, 8, 2, 6, 3, 9, 4, 10, 11, 10, 8, 4, 6, 5, 5, 5, 9, 6, 7, 2, 3, 8, 7, 3, 8, 9, 4, 8, 4, 4, 6, 4, 9, 10, 6, 7, 4, 11, 3, 12, 13, 12, 10, 5, 8, 8, 6, 6, 6, 5, 6, 6, 7, 3, 5, 10, 4, 8, 9, 0, 4, 8, 4, 5, 11, 8, 8, 3, 6, 10, 9, 4, 10]

cp's OEIS Frontend

A272895 a(n) is the largest natural number k such that the composite number (2n+1) 2^k+1 has a nontrivial divisor of the form h2^s+1 (h odd) with 2s>k. If such a natural number does not exist, we set a(n)=0.

Table of values

List of values

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

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

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