A329890 - cp's OEIS frontend

A329890 a(1) = 1; for n > 1, a(n) = sigma((2^n)-1) - sigma((2^(n-1))-1), where sigma is A000203, the sum of divisors.

n	a(n)
1	1
2	3
3	4
4	16
5	8
6	72
7	24
8	304
9	160
10	944
11	624
12	6576
13	-544
14	14336
15	16384
16	72544
17	19616
18	342528
19	50688
20	1475584
21	466176
22	3443712
23	2657376
24	29486880
25	-3340288
26	54808448
27	65971360
28	306781024
29	77647680
30	1475408064
31	132153344
32	5157119680
33	3054411072
34	12548176896
35	13343981568
36	130039259136
37	-28235160128
38	228451400256
39	269821673472

[1, 3, 4, 16, 8, 72, 24, 304, 160, 944, 624, 6576, -544, 14336, 16384, 72544, 19616, 342528, 50688, 1475584, 466176, 3443712, 2657376, 29486880, -3340288, 54808448, 65971360, 306781024, 77647680, 1475408064, 132153344, 5157119680, 3054411072, 12548176896, 13343981568, 130039259136, -28235160128, 228451400256, 269821673472]

cp's OEIS Frontend

A329890 a(1) = 1; for n > 1, a(n) = sigma((2^n)-1) - sigma((2^(n-1))-1), where sigma is A000203, the sum of divisors.

Table of values

List of values