The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 12 |
| 3 | 108 |
| 4 | 973 |
| 5 | 8760 |
| 6 | 78840 |
| 7 | 709561 |
| 8 | 6386052 |
| 9 | 57474468 |
| 10 | 517270213 |
| 11 | 4655431920 |
| 12 | 41898887280 |
| 13 | 377089985521 |
| 14 | 3393809869692 |
| 15 | 30544288827228 |
| 16 | 274898599445053 |
| 17 | 2474087395005480 |
[1,12,108,973,8760,78840,709561,6386052,57474468, 517270213,4655431920,41898887280,377089985521, 3393809869692,30544288827228,274898599445053, 2474087395005480] |