n | a(n) |
---|---|
1 | 2 |
2 | 4 |
3 | 18 |
4 | 100 |
5 | 578 |
6 | 3364 |
7 | 19602 |
8 | 114244 |
9 | 665858 |
10 | 3880900 |
11 | 22619538 |
12 | 131836324 |
13 | 768398402 |
14 | 4478554084 |
15 | 26102926098 |
16 | 152139002500 |
17 | 886731088898 |
18 | 5168247530884 |
19 | 30122754096402 |
20 | 175568277047524 |
21 | 1023286908188738 |
22 | 5964153172084900 |
23 | 34761632124320658 |
[2,4,18,100,578,3364,19602,114244,665858,3880900, 22619538,131836324,768398402,4478554084, 26102926098,152139002500,886731088898, 5168247530884,30122754096402,175568277047524, 1023286908188738,5964153172084900, 34761632124320658] |