The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 0 |
| 2 | 0 |
| 3 | 0 |
| 4 | 1 |
| 5 | 2 |
| 6 | 6 |
| 7 | 24 |
| 8 | 95 |
| 9 | 380 |
| 10 | 1520 |
| 11 | 6072 |
| 12 | 24253 |
| 13 | 96870 |
| 14 | 386910 |
| 15 | 1545368 |
| 16 | 6172403 |
| 17 | 24653392 |
| 18 | 98468904 |
| 19 | 393297808 |
| 20 | 1570883385 |
| 21 | 6274315690 |
| 22 | 25060445446 |
| 23 | 100094728568 |
| 24 | 399791564311 |
| 25 | 1596820303940 |
| 26 | 6377911168464 |
| 27 | 25474219467560 |
| 28 | 101747396653957 |
| 29 | 406392538897646 |
[0,0,0,0,1,2,6,24,95,380,1520,6072,24253,96870, 386910,1545368,6172403,24653392,98468904, 393297808,1570883385,6274315690,25060445446, 100094728568,399791564311,1596820303940, 6377911168464,25474219467560,101747396653957, 406392538897646] |