n | a(n) |
---|---|
0 | 1 |
1 | 1 |
2 | 4 |
3 | 18 |
4 | 126 |
5 | 1110 |
6 | 12120 |
7 | 156660 |
8 | 2341500 |
9 | 39701340 |
10 | 752839920 |
11 | 15785181720 |
12 | 362606123880 |
13 | 9055825538760 |
14 | 244296192460320 |
15 | 7079382509799600 |
16 | 219321853964413200 |
17 | 7233629128601475600 |
18 | 253054306933115688000 |
19 | 9358989706213886138400 |
20 | 364860828050107348159200 |
[1,1,4,18,126,1110,12120,156660,2341500,39701340, 752839920,15785181720,362606123880,9055825538760, 244296192460320,7079382509799600, 219321853964413200,7233629128601475600, 253054306933115688000,9358989706213886138400, 364860828050107348159200] |