n | a(n) |
---|---|
0 | 0 |
1 | 0 |
2 | 1 |
3 | 4 |
4 | 20 |
5 | 100 |
6 | 568 |
7 | 3480 |
8 | 23552 |
9 | 172280 |
10 | 1369600 |
11 | 11687996 |
12 | 107154944 |
13 | 1046876220 |
14 | 10891574272 |
15 | 119977808752 |
16 | 1397745975296 |
17 | 17147547551920 |
18 | 221248695107584 |
19 | 2992325932512948 |
20 | 42370119842398208 |
21 | 626422742409351380 |
22 | 9659199474524225536 |
23 | 154997830582262971784 |
[0,0,1,4,20,100,568,3480,23552,172280,1369600, 11687996,107154944,1046876220,10891574272, 119977808752,1397745975296,17147547551920, 221248695107584,2992325932512948, 42370119842398208,626422742409351380, 9659199474524225536,154997830582262971784] |