n | a(n) |
---|---|
0 | 1 |
1 | 0 |
2 | 2 |
3 | 3 |
4 | 20 |
5 | 60 |
6 | 345 |
7 | 1400 |
8 | 7770 |
9 | 36876 |
10 | 204876 |
11 | 1062600 |
12 | 5984352 |
13 | 32772168 |
14 | 187727826 |
15 | 1065491427 |
16 | 6206538910 |
17 | 36123454224 |
18 | 213645926208 |
19 | 1266954939822 |
20 | 7593846587496 |
21 | 45694598654640 |
22 | 277066122022872 |
23 | 1686973019649060 |
24 | 10331412410444280 |
25 | 63524084460496480 |
26 | 392411097399517800 |
[1,0,2,3,20,60,345,1400,7770,36876,204876,1062600, 5984352,32772168,187727826,1065491427,6206538910, 36123454224,213645926208,1266954939822, 7593846587496,45694598654640,277066122022872, 1686973019649060,10331412410444280, 63524084460496480,392411097399517800] |