A137323 - cp's OEIS frontend

A137323 a(n) = sum(d divides n, 2^(n/d-1) - 1 ), omitting d=1 and d=n.

n	a(n)
1	0
2	0
3	0
4	1
5	0
6	4
7	0
8	8
9	3
10	16
11	0
12	42
13	0
14	64
15	18
16	135
17	0
18	290
19	0
20	534
21	66
22	1024
23	0
24	2216
25	15
26	4096
27	258
28	8262
29	0
30	16944
31	0
32	32902
33	1026
34	65536
35	78
36	133415
37	0
38	262144
39	4098
40	524948
41	0
42	1056864
43	0
44	2098182
45	16656
46	4194304
47	0
48	8423590
49	63
50	16777742

[0, 0, 0, 1, 0, 4, 0, 8, 3, 16, 0, 42, 0, 64, 18, 135, 0, 290, 0, 534, 66, 1024, 0, 2216, 15, 4096, 258, 8262, 0, 16944, 0, 32902, 1026, 65536, 78, 133415, 0, 262144, 4098, 524948, 0, 1056864, 0, 2098182, 16656, 4194304, 0, 8423590, 63, 16777742]

cp's OEIS Frontend

A137323 a(n) = sum(d divides n, 2^(n/d-1) - 1 ), omitting d=1 and d=n.

Table of values

List of values