n | a(n) |
---|---|
1 | 4 |
2 | 120 |
3 | 1232 |
4 | 8656 |
5 | 50756 |
6 | 263816 |
7 | 1378418 |
8 | 6579675 |
9 | 29397762 |
10 | 123759215 |
11 | 496112681 |
12 | 1900666919 |
13 | 6979266540 |
14 | 24609313384 |
15 | 83512254200 |
16 | 273448859847 |
17 | 866039269080 |
18 | 2658909119696 |
19 | 7930100322771 |
20 | 23019222158010 |
21 | 65147052918163 |
[4,120,1232,8656,50756,263816,1378418,6579675, 29397762,123759215,496112681,1900666919, 6979266540,24609313384,83512254200,273448859847, 866039269080,2658909119696,7930100322771, 23019222158010,65147052918163] |