A307521 - cp's OEIS frontend

A307521 Expansion of Product_{k>=1} ((1 + x)^k + x^k)/((1 + x)^k - x^k).

n	a(n)
0	1
1	2
2	2
3	2
4	0
5	2
6	-2
7	2
8	0
9	-4
10	8
11	-4
12	-26
13	112
14	-288
15	560
16	-832
17	782
18	274
19	-3378
20	9424
21	-17498
22	21182
23	-2154
24	-78180
25	284594
26	-700018
27	1381802
28	-2250316
29	2877674
30	-2172870
31	-1955998
32	12715122
33	-33812990
34	67322842
35	-108956110
36	139447006
37	-110023870
38	-83188990
39	651268018

[1, 2, 2, 2, 0, 2, -2, 2, 0, -4, 8, -4, -26, 112, -288, 560, -832, 782, 274, -3378, 9424, -17498, 21182, -2154, -78180, 284594, -700018, 1381802, -2250316, 2877674, -2172870, -1955998, 12715122, -33812990, 67322842, -108956110, 139447006, -110023870, -83188990, 651268018]

cp's OEIS Frontend

A307521 Expansion of Product_{k>=1} ((1 + x)^k + x^k)/((1 + x)^k - x^k).

Table of values

List of values