A387512 - cp's OEIS frontend

A387512 a(n) = Sum_{k=0..floor(n/3)} 2^k * 3^(n-2k) binomial(n-2*k,k)^2.

n	a(n)
0	1
1	3
2	9
3	33
4	153
5	729
6	3357
7	15309
8	70713
9	331425
10	1565325
11	7418061
12	35250633
13	168030369
14	803361645
15	3850647741
16	18495465561
17	88998869313
18	428955792525
19	2070533412333
20	10007606103273
21	48428342800353
22	234607598151597
23	1137670448889501
24	5521881103615737

[1, 3, 9, 33, 153, 729, 3357, 15309, 70713, 331425, 1565325, 7418061, 35250633, 168030369, 803361645, 3850647741, 18495465561, 88998869313, 428955792525, 2070533412333, 10007606103273, 48428342800353, 234607598151597, 1137670448889501, 5521881103615737]

cp's OEIS Frontend

A387512 a(n) = Sum_{k=0..floor(n/3)} 2^k * 3^(n-2k) binomial(n-2*k,k)^2.

Table of values

List of values

cp's OEIS Frontend

A387512 a(n) = Sum_{k=0..floor(n/3)} 2^k * 3^(n-2*k) * binomial(n-2*k,k)^2.

Table of values

List of values

A387512 a(n) = Sum_{k=0..floor(n/3)} 2^k * 3^(n-2k) binomial(n-2*k,k)^2.