n | a(n) |
---|---|
0 | 1 |
1 | 4 |
2 | 12 |
3 | 36 |
4 | 116 |
5 | 416 |
6 | 1680 |
7 | 7656 |
8 | 39256 |
9 | 225348 |
10 | 1439868 |
11 | 10179116 |
12 | 79153484 |
13 | 673262240 |
14 | 6231517920 |
15 | 62461031920 |
16 | 675005395152 |
17 | 7832909636740 |
18 | 97238472215564 |
19 | 1286967352638292 |
20 | 18102901048062404 |
21 | 269852768731391808 |
[1,4,12,36,116,416,1680,7656,39256,225348,1439868, 10179116,79153484,673262240,6231517920, 62461031920,675005395152,7832909636740, 97238472215564,1286967352638292,18102901048062404, 269852768731391808] |