n | a(n) |
---|---|
0 | 0 |
1 | 0 |
2 | 0 |
3 | 0 |
4 | 2 |
5 | 6 |
6 | 20 |
7 | 60 |
8 | 176 |
9 | 510 |
10 | 1484 |
11 | 4314 |
12 | 12624 |
13 | 37126 |
14 | 109864 |
15 | 326958 |
16 | 978528 |
17 | 2943384 |
18 | 8895792 |
19 | 27001378 |
20 | 82281216 |
21 | 251636434 |
22 | 772101086 |
23 | 2376186784 |
24 | 7333094178 |
25 | 22688117658 |
26 | 70360646672 |
27 | 218678194238 |
28 | 681016789056 |
[0,0,0,0,2,6,20,60,176,510,1484,4314,12624,37126, 109864,326958,978528,2943384,8895792,27001378, 82281216,251636434,772101086,2376186784, 7333094178,22688117658,70360646672,218678194238, 681016789056] |