A221881 - OEIS

A221881 as a simple table

n	a(n)
1	1
2	1
3	3
4	1
5	5
6	7
7	1
8	7
9	13
10	15
11	1
12	9
13	21
14	29
15	31
16	1
17	11
18	31
19	51
20	61
21	63
22	1
23	13
24	43
25	83
26	113
27	125
28	127
29	1
30	15
31	57
32	127
33	197
34	239
35	253
36	255
37	1
38	17
39	73
40	185
41	325
42	437
43	493
44	509
45	511
46	1
47	19
48	91
49	259
50	511
51	763
52	931
53	1003
54	1021
55	1023

[1,1,3,1,5,7,1,7,13,15,1,9,21,29,31,1,11,31,51,61, 63,1,13,43,83,113,125,127,1,15,57,127,197,239,253, 255,1,17,73,185,325,437,493,509,511,1,19,91,259, 511,763,931,1003,1021,1023]