n | a(n) |
---|---|
1 | 4 |
2 | 10 |
3 | 30 |
4 | 550 |
5 | 1540 |
6 | 48070 |
7 | 223300 |
8 | 2634940 |
9 | 402610950 |
10 | 1570545340 |
11 | 13960282700 |
12 | 5677137442900 |
13 | 248297918605660 |
[4,10,30,550,1540,48070,223300,2634940,402610950, 1570545340,13960282700,5677137442900, 248297918605660] |