A099781 - cp's OEIS frontend

A099781 a(n) = Sum_{k=0..floor(n/3)} C(n-k,2k) 4^(n-3*k).

n	a(n)
0	1
1	4
2	16
3	65
4	268
5	1120
6	4737
7	20244
8	87280
9	379073
10	1656348
11	7272896
12	32060673
13	141775396
14	628505296
15	2791696705
16	12419264300
17	55315472416
18	246607247233
19	1100229683508
20	4911436984752
21	21934428189121
22	97992663440444

[1, 4, 16, 65, 268, 1120, 4737, 20244, 87280, 379073, 1656348, 7272896, 32060673, 141775396, 628505296, 2791696705, 12419264300, 55315472416, 246607247233, 1100229683508, 4911436984752, 21934428189121, 97992663440444]

cp's OEIS Frontend

A099781 a(n) = Sum_{k=0..floor(n/3)} C(n-k,2k) 4^(n-3*k).

Table of values

List of values

cp's OEIS Frontend

A099781 a(n) = Sum_{k=0..floor(n/3)} C(n-k,2*k) * 4^(n-3*k).

Table of values

List of values

A099781 a(n) = Sum_{k=0..floor(n/3)} C(n-k,2k) 4^(n-3*k).