A387604 - cp's OEIS frontend

A387604 a(n) = (1/2) * Sum_{k=0..floor(n/3)} 3^(n-2k) binomial(2n-4k+2,2*k+1).

n	a(n)
0	1
1	6
2	27
3	114
4	495
5	2214
6	9990
7	44982
8	201933
9	905526
10	4061016
11	18217710
12	81735156
13	366712272
14	1645244379
15	7381235808
16	33115172733
17	148568241906
18	666539094105
19	2990373257970
20	13416063062094
21	60190050847500
22	270037644213267
23	1211501390490972
24	5435300133382176

[1, 6, 27, 114, 495, 2214, 9990, 44982, 201933, 905526, 4061016, 18217710, 81735156, 366712272, 1645244379, 7381235808, 33115172733, 148568241906, 666539094105, 2990373257970, 13416063062094, 60190050847500, 270037644213267, 1211501390490972, 5435300133382176]

cp's OEIS Frontend

A387604 a(n) = (1/2) * Sum_{k=0..floor(n/3)} 3^(n-2k) binomial(2n-4k+2,2*k+1).

Table of values

List of values

cp's OEIS Frontend

A387604 a(n) = (1/2) * Sum_{k=0..floor(n/3)} 3^(n-2*k) * binomial(2*n-4*k+2,2*k+1).

Table of values

List of values

A387604 a(n) = (1/2) * Sum_{k=0..floor(n/3)} 3^(n-2k) binomial(2n-4k+2,2*k+1).