A039721 - cp's OEIS frontend

A039721 a(1) = 1, a(m+1) = 2*Sum_{k=1..floor((m+1)/2)} a(m+1-k).

n	a(n)
1	1
2	2
3	4
4	12
5	32
6	96
7	280
8	840
9	2496
10	7488
11	22400
12	67200
13	201408
14	604224
15	1812112
16	5436336
17	16307328
18	48921984
19	146760960
20	440282880
21	1320833664
22	3962500992
23	11887458176
24	35662374528
25	106986989184
26	320960967552
27	962882499840
28	2888647499520
29	8665941290112

[1, 2, 4, 12, 32, 96, 280, 840, 2496, 7488, 22400, 67200, 201408, 604224, 1812112, 5436336, 16307328, 48921984, 146760960, 440282880, 1320833664, 3962500992, 11887458176, 35662374528, 106986989184, 320960967552, 962882499840, 2888647499520, 8665941290112]

cp's OEIS Frontend

A039721 a(1) = 1, a(m+1) = 2*Sum_{k=1..floor((m+1)/2)} a(m+1-k).

Table of values

List of values