A372894 - cp's OEIS frontend

A372894 A positive integer 2^k*m, where m is odd and k >= 0, belongs to this sequence iff the Jacobi symbol (F_n/m) = -1 for only a finite number of Fermat numbers F_n = A000215(n).

n	a(n)
1	1
2	2
3	4
4	8
5	9
6	13
7	15
8	16
9	17
10	18
11	21
12	25
13	26
14	30
15	32
16	34
17	35
18	36
19	42
20	49
21	50
22	52
23	60
24	64
25	68
26	70
27	72
28	81
29	84
30	97
31	98
32	100
33	104
34	117
35	120
36	121
37	123
38	128
39	135
40	136
41	140
42	144
43	153
44	162
45	168
46	169
47	189
48	193
49	194
50	195
51	196
52	200
53	205
54	208
55	221
56	225
57	234
58	240
59	241
60	242
61	246
62	255
63	256
64	257
65	270
66	272
67	273
68	280
69	287
70	288
71	289

[1, 2, 4, 8, 9, 13, 15, 16, 17, 18, 21, 25, 26, 30, 32, 34, 35, 36, 42, 49, 50, 52, 60, 64, 68, 70, 72, 81, 84, 97, 98, 100, 104, 117, 120, 121, 123, 128, 135, 136, 140, 144, 153, 162, 168, 169, 189, 193, 194, 195, 196, 200, 205, 208, 221, 225, 234, 240, 241, 242, 246, 255, 256, 257, 270, 272, 273, 280, 287, 288, 289]

cp's OEIS Frontend

A372894 A positive integer 2^k*m, where m is odd and k >= 0, belongs to this sequence iff the Jacobi symbol (F_n/m) = -1 for only a finite number of Fermat numbers F_n = A000215(n).

Table of values

List of values

n	a(n)
1	1
2	2
3	4
4	8
5	9
6	13
7	15
8	16
9	17
10	18
11	21
12	25
13	26
14	30
15	32
16	34
17	35
18	36
19	42
20	49
21	50
22	52
23	60
24	64
25	68
26	70
27	72
28	81
29	84
30	97
31	98
32	100
33	104
34	117
35	120
36	121
37	123
38	128
39	135
40	136
41	140
42	144
43	153
44	162
45	168
46	169
47	189
48	193
49	194
50	195
51	196
52	200
53	205
54	208
55	221
56	225
57	234
58	240
59	241
60	242
61	246
62	255
63	256
64	257
65	270
66	272
67	273
68	280
69	287
70	288
71	289

n	a(n)
1	1
2	2
3	4
4	8
5	9
6	13
7	15
8	16
9	17
10	18
11	21
12	25
13	26
14	30
15	32
16	34
17	35
18	36
19	42
20	49
21	50
22	52
23	60
24	64
25	68
26	70
27	72
28	81
29	84
30	97
31	98
32	100
33	104
34	117
35	120
36	121
37	123
38	128
39	135
40	136
41	140
42	144
43	153
44	162
45	168
46	169
47	189
48	193
49	194
50	195
51	196
52	200
53	205
54	208
55	221
56	225
57	234
58	240
59	241
60	242
61	246
62	255
63	256
64	257
65	270
66	272
67	273
68	280
69	287
70	288
71	289

n	a(n)
1	1
2	2
3	4
4	8
5	9
6	13
7	15
8	16
9	17
10	18
11	21
12	25
13	26
14	30
15	32
16	34
17	35
18	36
19	42
20	49
21	50
22	52
23	60
24	64
25	68
26	70
27	72
28	81
29	84
30	97
31	98
32	100
33	104
34	117
35	120
36	121
37	123
38	128
39	135
40	136
41	140
42	144
43	153
44	162
45	168
46	169
47	189
48	193
49	194
50	195
51	196
52	200
53	205
54	208
55	221
56	225
57	234
58	240
59	241
60	242
61	246
62	255
63	256
64	257
65	270
66	272
67	273
68	280
69	287
70	288
71	289