A085570 - cp's OEIS frontend

A085570 If n mod 2 = 0 then 2Sum(floor(C(n,w)/(2w+1)),w=0..n/2-1)+floor(C(n,n/2)/(n+1)) otherwise 2Sum(floor(C(n,w)/(2w+1)),w=0..(n-1)/2).

n	a(n)
0	1
1	2
2	2
3	4
4	5
5	8
6	14
7	24
8	39
9	74
10	128
11	232
12	423
13	776
14	1426
15	2660
16	4931
17	9268
18	17346
19	32840
20	61903
21	117832
22	223410
23	427156
24	813812
25	1561830
26	2987535
27	5751742
28	11039759
29	21312036
30	41025866
31	79386066
32	153208323
33	297072312
34	574604611
35	1116186954
36	2163216427

[1, 2, 2, 4, 5, 8, 14, 24, 39, 74, 128, 232, 423, 776, 1426, 2660, 4931, 9268, 17346, 32840, 61903, 117832, 223410, 427156, 813812, 1561830, 2987535, 5751742, 11039759, 21312036, 41025866, 79386066, 153208323, 297072312, 574604611, 1116186954, 2163216427]

cp's OEIS Frontend

A085570 If n mod 2 = 0 then 2Sum(floor(C(n,w)/(2w+1)),w=0..n/2-1)+floor(C(n,n/2)/(n+1)) otherwise 2Sum(floor(C(n,w)/(2w+1)),w=0..(n-1)/2).

Table of values

List of values

cp's OEIS Frontend

A085570 If n mod 2 = 0 then 2*Sum(floor(C(n,w)/(2*w+1)),w=0..n/2-1)+floor(C(n,n/2)/(n+1)) otherwise 2*Sum(floor(C(n,w)/(2*w+1)),w=0..(n-1)/2).

Table of values

List of values

A085570 If n mod 2 = 0 then 2Sum(floor(C(n,w)/(2w+1)),w=0..n/2-1)+floor(C(n,n/2)/(n+1)) otherwise 2Sum(floor(C(n,w)/(2w+1)),w=0..(n-1)/2).