n | a(n) |
---|---|
1 | 0 |
2 | 0 |
3 | 1 |
4 | 2 |
5 | 6 |
6 | 22 |
7 | 102 |
8 | 506 |
9 | 2952 |
10 | 18502 |
11 | 131112 |
12 | 991226 |
13 | 8271792 |
14 | 73176262 |
15 | 703077552 |
16 | 7121578106 |
17 | 77437418112 |
18 | 883521487942 |
19 | 10726837356672 |
20 | 136104948161786 |
21 | 1825110309733632 |
[0,0,1,2,6,22,102,506,2952,18502,131112,991226, 8271792,73176262,703077552,7121578106,77437418112, 883521487942,10726837356672,136104948161786, 1825110309733632] |