The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 3 |
| 3 | 9 |
| 4 | 32 |
| 5 | 106 |
| 6 | 426 |
| 7 | 1630 |
| 8 | 6384 |
| 9 | 25946 |
| 10 | 108308 |
| 11 | 445189 |
| 12 | 1877503 |
| 13 | 8022260 |
| 14 | 34370984 |
| 15 | 148012675 |
| 16 | 643610626 |
| 17 | 2817324764 |
| 18 | 12368693445 |
| 19 | 54448245375 |
| 20 | 241561372630 |
| 21 | 1075228964553 |
| 22 | 4787473330615 |
| 23 | 21431052382410 |
| 24 | 96316712546439 |
| 25 | 433054378646430 |
| 26 | 1952963046254572 |
| 27 | 8836449646395901 |
| 28 | 40041198913314657 |
[1,1,3,9,32,106,426,1630,6384,25946,108308,445189, 1877503,8022260,34370984,148012675,643610626, 2817324764,12368693445,54448245375,241561372630, 1075228964553,4787473330615,21431052382410, 96316712546439,433054378646430,1952963046254572, 8836449646395901,40041198913314657] |