n | a(n) |
---|---|
1 | 0 |
2 | 0 |
3 | 1 |
4 | 9 |
5 | 57 |
6 | 315 |
7 | 1629 |
8 | 8127 |
9 | 39718 |
10 | 191754 |
11 | 919035 |
12 | 4385799 |
13 | 20879100 |
14 | 99276840 |
15 | 471848195 |
16 | 2242864575 |
17 | 10665998760 |
18 | 50757180840 |
19 | 241743946635 |
20 | 1152434818755 |
21 | 5499250360025 |
22 | 26268118117731 |
23 | 125602004765391 |
[0,0,1,9,57,315,1629,8127,39718,191754,919035, 4385799,20879100,99276840,471848195,2242864575, 10665998760,50757180840,241743946635, 1152434818755,5499250360025,26268118117731, 125602004765391] |