The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 4 |
| 2 | 27 |
| 3 | 236 |
| 4 | 2380 |
| 5 | 26216 |
| 6 | 306495 |
| 7 | 3740572 |
| 8 | 47159772 |
| 9 | 609924536 |
| 10 | 8051939324 |
| 11 | 108110654120 |
| 12 | 1472276038688 |
| 13 | 20292738170064 |
| 14 | 282614171731527 |
| 15 | 3971576995998588 |
| 16 | 56256063139701916 |
| 17 | 802448704561822616 |
[1,4,27,236,2380,26216,306495,3740572,47159772, 609924536,8051939324,108110654120,1472276038688, 20292738170064,282614171731527,3971576995998588, 56256063139701916,802448704561822616] |