n | a(n) |
---|---|
0 | 0 |
1 | 0 |
2 | 1 |
3 | 7 |
4 | 31 |
5 | 139 |
6 | 609 |
7 | 2677 |
8 | 11827 |
9 | 52648 |
10 | 236071 |
11 | 1065774 |
12 | 4841428 |
13 | 22115678 |
14 | 101531221 |
15 | 468224323 |
16 | 2168076055 |
17 | 10076177264 |
18 | 46986612235 |
19 | 219777649588 |
20 | 1030892581741 |
21 | 4848039893338 |
22 | 22853638285655 |
23 | 107970202258065 |
[0,0,1,7,31,139,609,2677,11827,52648,236071, 1065774,4841428,22115678,101531221,468224323, 2168076055,10076177264,46986612235,219777649588, 1030892581741,4848039893338,22853638285655, 107970202258065] |