n | a(n) |
---|---|
0 | 1 |
1 | 4 |
2 | 44 |
3 | 204 |
4 | 908 |
5 | 3744 |
6 | 15316 |
7 | 61920 |
8 | 248220 |
9 | 994992 |
10 | 3980164 |
11 | 15931876 |
12 | 63736548 |
13 | 254959532 |
14 | 1019922416 |
15 | 4079716172 |
[1,4,44,204,908,3744,15316,61920,248220,994992, 3980164,15931876,63736548,254959532,1019922416, 4079716172] |