The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 7 |
| 3 | 28 |
| 4 | 105 |
| 5 | 322 |
| 6 | 952 |
| 7 | 2541 |
| 8 | 6539 |
| 9 | 15833 |
| 10 | 37148 |
| 11 | 83594 |
| 12 | 183289 |
| 13 | 389520 |
| 14 | 809820 |
| 15 | 1643375 |
| 16 | 3272797 |
| 17 | 6390745 |
| 18 | 12279337 |
| 19 | 23208483 |
| 20 | 43252360 |
| 21 | 79483096 |
| 22 | 144265338 |
| 23 | 258673983 |
| 24 | 458747540 |
| 25 | 804877837 |
| 26 | 1398356706 |
| 27 | 2406328974 |
| 28 | 4104352128 |
| 29 | 6940717598 |
| 30 | 11643270856 |
[1,1,7,28,105,322,952,2541,6539,15833,37148,83594, 183289,389520,809820,1643375,3272797,6390745, 12279337,23208483,43252360,79483096,144265338, 258673983,458747540,804877837,1398356706, 2406328974,4104352128,6940717598,11643270856] |