A387603 - cp's OEIS frontend

A387603 a(n) = (1/2) * Sum_{k=0..floor(n/3)} 2^(n-k) * binomial(2n-4k+2,2*k+1).

n	a(n)
0	1
1	4
2	12
3	40
4	160
5	640
6	2416
7	8960
8	33664
9	127744
10	484096
11	1827840
12	6896896
13	26049536
14	98440192
15	371939328
16	1404997632
17	5307301888
18	20049424384
19	75742707712
20	286136467456
21	1080936235008
22	4083451559936
23	15426119532544
24	58275554459648
25	220148448624640
26	831657574400000

[1, 4, 12, 40, 160, 640, 2416, 8960, 33664, 127744, 484096, 1827840, 6896896, 26049536, 98440192, 371939328, 1404997632, 5307301888, 20049424384, 75742707712, 286136467456, 1080936235008, 4083451559936, 15426119532544, 58275554459648, 220148448624640, 831657574400000]

cp's OEIS Frontend

A387603 a(n) = (1/2) * Sum_{k=0..floor(n/3)} 2^(n-k) * binomial(2n-4k+2,2*k+1).

Table of values

List of values

cp's OEIS Frontend

A387603 a(n) = (1/2) * Sum_{k=0..floor(n/3)} 2^(n-k) * binomial(2*n-4*k+2,2*k+1).

Table of values

List of values

A387603 a(n) = (1/2) * Sum_{k=0..floor(n/3)} 2^(n-k) * binomial(2n-4k+2,2*k+1).