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 | 0 |
| 5 | 0 |
| 6 | 1 |
| 7 | 1 |
| 8 | 2 |
| 9 | 2 |
| 10 | 5 |
| 11 | 4 |
| 12 | 16 |
| 13 | 13 |
| 14 | 64 |
| 15 | 98 |
| 16 | 597 |
| 17 | 2064 |
| 18 | 22472 |
| 19 | 112814 |
| 20 | 4799607 |
| 21 | 31138903 |
| 22 | 4207941575 |
| 23 | 115979716284 |
| 24 | 13482672620149 |
[0,0,0,0,0,0,1,1,2,2,5,4,16,13,64,98,597,2064, 22472,112814,4799607,31138903,4207941575, 115979716284,13482672620149] |