The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 4 | 1 |
| 5 | 3 |
| 6 | 21 |
| 7 | 59 |
| 8 | 198 |
| 9 | 703 |
| 10 | 2568 |
| 11 | 8421 |
| 12 | 26165 |
| 13 | 78074 |
| 14 | 229881 |
| 15 | 668082 |
| 16 | 1928220 |
| 17 | 5523946 |
| 18 | 15745682 |
| 19 | 44666804 |
| 20 | 126251748 |
| 21 | 355692380 |
| 22 | 999498933 |
| 23 | 2802212026 |
| 24 | 7841587533 |
| 25 | 21907928927 |
| 26 | 61123152811 |
| 27 | 170333279738 |
| 28 | 474197771123 |
| 29 | 1319004492132 |
| 30 | 3666181193067 |
| 31 | 10183729521212 |
[1,3,21,59,198,703,2568,8421,26165,78074,229881, 668082,1928220,5523946,15745682,44666804, 126251748,355692380,999498933,2802212026, 7841587533,21907928927,61123152811,170333279738, 474197771123,1319004492132,3666181193067, 10183729521212] |