n | a(n) |
---|---|
0 | 0 |
1 | 1 |
2 | 4 |
3 | 21 |
4 | 120 |
5 | 697 |
6 | 4060 |
7 | 23661 |
8 | 137904 |
9 | 803761 |
10 | 4684660 |
11 | 27304197 |
12 | 159140520 |
13 | 927538921 |
14 | 5406093004 |
15 | 31509019101 |
16 | 183648021600 |
17 | 1070379110497 |
18 | 6238626641380 |
19 | 36361380737781 |
20 | 211929657785304 |
21 | 1235216565974041 |
22 | 7199369738058940 |
23 | 41961001862379597 |
[0,1,4,21,120,697,4060,23661,137904,803761, 4684660,27304197,159140520,927538921,5406093004, 31509019101,183648021600,1070379110497, 6238626641380,36361380737781,211929657785304, 1235216565974041,7199369738058940, 41961001862379597] |