The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 13 |
| 3 | 54 |
| 4 | 171 |
| 5 | 487 |
| 6 | 1324 |
| 7 | 3525 |
| 8 | 9297 |
| 9 | 24418 |
| 10 | 64015 |
| 11 | 167691 |
| 12 | 439128 |
| 13 | 1149769 |
| 14 | 3010261 |
| 15 | 7881102 |
| 16 | 20633139 |
| 17 | 54018415 |
| 18 | 141422212 |
| 19 | 370248333 |
| 20 | 969322905 |
| 21 | 2537720506 |
| 22 | 6643838743 |
| 23 | 17393795859 |
| 24 | 45537548976 |
| 25 | 119218851217 |
| 26 | 312119004829 |
[1,13,54,171,487,1324,3525,9297,24418,64015, 167691,439128,1149769,3010261,7881102,20633139, 54018415,141422212,370248333,969322905,2537720506, 6643838743,17393795859,45537548976,119218851217, 312119004829] |