The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 10 |
| 3 | 420 |
| 4 | 43960 |
| 5 | 9347800 |
| 6 | 3513910400 |
| 7 | 2131249120000 |
| 8 | 1952028782704000 |
| 9 | 2568150610833808000 |
| 10 | 4666919676058159520000 |
| 11 | 11351087418588355518080000 |
| 12 | 36008099327884173922432000000 |
| 13 | 145785514242304854141480256000000 |
| 14 | 739598808823839440680777500928000000 |
| 15 | 4627885522642342503645368137231360000000 |
[1,1,10,420,43960,9347800,3513910400, 2131249120000,1952028782704000, 2568150610833808000,4666919676058159520000, 11351087418588355518080000, 36008099327884173922432000000, 145785514242304854141480256000000, 739598808823839440680777500928000000, 4627885522642342503645368137231360000000] |