A272894 - cp's OEIS frontend

A272894 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 s>k. If such a natural number does not exist, we set a(n)=0.

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

[0, 0, 0, 1, 0, 2, 1, 0, 1, 3, 2, 0, 1, 1, 2, 2, 0, 4, 3, 0, 2, 1, 1, 2, 1, 2, 3, 3, 1, 1, 2, 0, 2, 5, 4, 2, 3, 0, 1, 1, 2, 2, 1, 3, 2, 3, 1, 0, 1, 0, 4, 4, 0, 2, 3, 2, 0, 1, 1, 2, 3, 2, 0, 3, 1, 6, 5, 0, 4, 1, 2, 1, 3, 1, 1, 2, 3, 3, 2, 2, 2, 3, 0, 4, 3, 4, 2, 1, 1, 0, 3, 0, 2, 1, 3, 2, 1, 1, 5, 5, 2]

cp's OEIS Frontend

A272894 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 s>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	0
2	0
3	1
4	0
5	2
6	1
7	0
8	1
9	3
10	2
11	0
12	1
13	1
14	2
15	2
16	0
17	4
18	3
19	0
20	2
21	1
22	1
23	2
24	1
25	2
26	3
27	3
28	1
29	1
30	2
31	0
32	2
33	5
34	4
35	2
36	3
37	0
38	1
39	1
40	2
41	2
42	1
43	3
44	2
45	3
46	1
47	0
48	1
49	0
50	4
51	4
52	0
53	2
54	3
55	2
56	0
57	1
58	1
59	2
60	3
61	2
62	0
63	3
64	1
65	6
66	5
67	0
68	4
69	1
70	2
71	1
72	3
73	1
74	1
75	2
76	3
77	3
78	2
79	2
80	2
81	3
82	0
83	4
84	3
85	4
86	2
87	1
88	1
89	0
90	3
91	0
92	2
93	1
94	3
95	2
96	1
97	1
98	5
99	5
100	2

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

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