The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 2 | 1 |
| 3 | 1 |
| 4 | 1 |
| 5 | 4 |
| 6 | 11 |
| 7 | 35 |
| 8 | 125 |
| 9 | 445 |
| 10 | 1699 |
| 11 | 6668 |
| 12 | 26935 |
| 13 | 112111 |
| 14 | 476674 |
| 15 | 2072146 |
| 16 | 9182141 |
| 17 | 41406119 |
| 18 | 189830984 |
| 19 | 883549848 |
| 20 | 4171598085 |
| 21 | 19962224926 |
| 22 | 96746007976 |
| 23 | 474586282085 |
| 24 | 2355104582435 |
| 25 | 11817111373152 |
| 26 | 59928222117495 |
| 27 | 307045555880793 |
| 28 | 1588825668984517 |
[1,1,1,4,11,35,125,445,1699,6668,26935,112111, 476674,2072146,9182141,41406119,189830984, 883549848,4171598085,19962224926,96746007976, 474586282085,2355104582435,11817111373152, 59928222117495,307045555880793,1588825668984517] |