The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 3 |
| 3 | 10 |
| 4 | 44 |
| 5 | 234 |
| 6 | 1470 |
| 7 | 10656 |
| 8 | 87624 |
| 9 | 806280 |
| 10 | 8211000 |
| 11 | 91707120 |
| 12 | 1114793280 |
| 13 | 14653936080 |
| 14 | 207138844080 |
| 15 | 3133376225280 |
| 16 | 50508380361600 |
| 17 | 864341342363520 |
| 18 | 15650522186302080 |
| 19 | 298948657681094400 |
| 20 | 6007868689030387200 |
| 21 | 126719410500228268800 |
| 22 | 2799004485444175008000 |
| 23 | 64613640777996615782400 |
[1,1,3,10,44,234,1470,10656,87624,806280,8211000, 91707120,1114793280,14653936080,207138844080, 3133376225280,50508380361600,864341342363520, 15650522186302080,298948657681094400, 6007868689030387200,126719410500228268800, 2799004485444175008000,64613640777996615782400] |