The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 5 |
| 3 | 16 |
| 4 | 64 |
| 5 | 288 |
| 6 | 1354 |
| 7 | 6496 |
| 8 | 31728 |
| 9 | 157818 |
| 10 | 798098 |
| 11 | 4091712 |
| 12 | 21211165 |
| 13 | 110969430 |
| 14 | 585116287 |
| 15 | 3106334810 |
| 16 | 16590881379 |
| 17 | 89085610328 |
| 18 | 480627775528 |
| 19 | 2604103448334 |
| 20 | 14163573236255 |
| 21 | 77302955664902 |
| 22 | 423245859576867 |
| 23 | 2324046398587426 |
| 24 | 12795255089638583 |
| 25 | 70617777139027756 |
[1,2,5,16,64,288,1354,6496,31728,157818,798098, 4091712,21211165,110969430,585116287,3106334810, 16590881379,89085610328,480627775528, 2604103448334,14163573236255,77302955664902, 423245859576867,2324046398587426, 12795255089638583,70617777139027756] |