n | a(n) |
---|---|
0 | 0 |
1 | 0 |
2 | 0 |
3 | 1 |
4 | 4 |
5 | 20 |
6 | 90 |
7 | 455 |
8 | 2352 |
9 | 13132 |
10 | 76540 |
11 | 473660 |
12 | 3069220 |
13 | 20922330 |
14 | 149021600 |
15 | 1109629885 |
16 | 8604815520 |
17 | 69437698160 |
18 | 581661169640 |
19 | 5051885815603 |
20 | 45411759404560 |
21 | 421977921782270 |
22 | 4047693372023070 |
23 | 40034523497947132 |
24 | 407818256494533984 |
25 | 4274309903558446900 |
[0,0,0,1,4,20,90,455,2352,13132,76540,473660, 3069220,20922330,149021600,1109629885,8604815520, 69437698160,581661169640,5051885815603, 45411759404560,421977921782270,4047693372023070, 40034523497947132,407818256494533984, 4274309903558446900] |