A100068 - cp's OEIS frontend

A100068 a(n) = Sum_{k=0..floor(n/2)} binomial(n,k)3^(n-2k).

n	a(n)
0	1
1	3
2	11
3	36
4	123
5	408
6	1370
7	4560
8	15235
9	50760
10	169326
11	564336
12	1881582
13	6271632
14	20907156
15	69689376
16	232304355
17	774343560
18	2581169510
19	8603882160
20	28679699578
21	95598937008
22	318663476076
23	1062211351776
24	3540705857998
25	11802351958608
26	39341178395660
27	131137257852000

[1, 3, 11, 36, 123, 408, 1370, 4560, 15235, 50760, 169326, 564336, 1881582, 6271632, 20907156, 69689376, 232304355, 774343560, 2581169510, 8603882160, 28679699578, 95598937008, 318663476076, 1062211351776, 3540705857998, 11802351958608, 39341178395660, 131137257852000]

cp's OEIS Frontend

A100068 a(n) = Sum_{k=0..floor(n/2)} binomial(n,k)3^(n-2k).

Table of values

List of values

cp's OEIS Frontend

A100068 a(n) = Sum_{k=0..floor(n/2)} binomial(n,k)*3^(n-2*k).

Table of values

List of values

A100068 a(n) = Sum_{k=0..floor(n/2)} binomial(n,k)3^(n-2k).