n | a(n) |
---|---|
0 | 1 |
1 | 4 |
2 | 20 |
3 | 112 |
4 | 676 |
5 | 4328 |
6 | 28912 |
7 | 199392 |
8 | 1409364 |
9 | 10157828 |
10 | 74375640 |
11 | 551715264 |
12 | 4137527408 |
13 | 31318286632 |
14 | 238958947328 |
15 | 1835960454272 |
16 | 14192132860868 |
17 | 110298595778872 |
18 | 861338925309604 |
19 | 6755283201399776 |
20 | 53185599585579640 |
[1,4,20,112,676,4328,28912,199392,1409364, 10157828,74375640,551715264,4137527408, 31318286632,238958947328,1835960454272, 14192132860868,110298595778872,861338925309604, 6755283201399776,53185599585579640] |