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 | 5 |
| 5 | 24 |
| 6 | 85 |
| 7 | 264 |
| 8 | 760 |
| 9 | 2080 |
| 10 | 5488 |
| 11 | 14080 |
| 12 | 35328 |
| 13 | 87040 |
| 14 | 211200 |
| 15 | 505856 |
| 16 | 1198080 |
| 17 | 2809856 |
| 18 | 6533120 |
| 19 | 15073280 |
| 20 | 34537472 |
| 21 | 78643200 |
| 22 | 178061312 |
| 23 | 401080320 |
| 24 | 899153920 |
| 25 | 2006974464 |
| 26 | 4461690880 |
| 27 | 9881780224 |
| 28 | 21810380800 |
| 29 | 47982837760 |
| 30 | 105243475968 |
[0,0,0,0,5,24,85,264,760,2080,5488,14080,35328, 87040,211200,505856,1198080,2809856,6533120, 15073280,34537472,78643200,178061312,401080320, 899153920,2006974464,4461690880,9881780224, 21810380800,47982837760,105243475968] |