A387509 - cp's OEIS frontend

A387509 a(n) = Sum_{k=0..floor(n/3)} 2^(n-k) * binomial(n-2*k,k)^2.

n	a(n)
0	1
1	2
2	4
3	12
4	48
5	176
6	592
7	2016
8	7168
9	25920
10	93440
11	336384
12	1216768
13	4425216
14	16143360
15	58993664
16	215965696
17	792154112
18	2910720000
19	10710884352
20	39464009728
21	145575002112
22	537583419392
23	1987177611264
24	7352243781632
25	27224715689984
26	100888181211136

[1, 2, 4, 12, 48, 176, 592, 2016, 7168, 25920, 93440, 336384, 1216768, 4425216, 16143360, 58993664, 215965696, 792154112, 2910720000, 10710884352, 39464009728, 145575002112, 537583419392, 1987177611264, 7352243781632, 27224715689984, 100888181211136]

cp's OEIS Frontend

A387509 a(n) = Sum_{k=0..floor(n/3)} 2^(n-k) * binomial(n-2*k,k)^2.

Table of values

List of values