The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 3 |
| 2 | 7 |
| 3 | 16 |
| 4 | 38 |
| 5 | 95 |
| 6 | 249 |
| 7 | 678 |
| 8 | 1901 |
| 9 | 5451 |
| 10 | 15906 |
| 11 | 47066 |
| 12 | 140868 |
| 13 | 425657 |
| 14 | 1296665 |
| 15 | 3977684 |
| 16 | 12276617 |
| 17 | 38094013 |
| 18 | 118768915 |
| 19 | 371875752 |
| 20 | 1168843808 |
| 21 | 3686549845 |
| 22 | 11664123048 |
| 23 | 37011249678 |
| 24 | 117750111763 |
| 25 | 375529083267 |
| 26 | 1200327617200 |
| 27 | 3844662925222 |
| 28 | 12338289374046 |
[1,3,7,16,38,95,249,678,1901,5451,15906,47066, 140868,425657,1296665,3977684,12276617,38094013, 118768915,371875752,1168843808,3686549845, 11664123048,37011249678,117750111763,375529083267, 1200327617200,3844662925222,12338289374046] |