The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 1 | 8 |
| 2 | 42 |
| 3 | 303 |
| 4 | 2574 |
| 5 | 22128 |
| 6 | 175180 |
| 7 | 1231170 |
| 8 | 7652503 |
| 9 | 42460424 |
| 10 | 212971589 |
| 11 | 977395362 |
| 12 | 4147719749 |
| 13 | 16420984346 |
| 14 | 61103700814 |
| 15 | 215040758842 |
| 16 | 719522481940 |
| 17 | 2299243641848 |
| 18 | 7043942786447 |
| 19 | 20758083457211 |
| 20 | 59015575393057 |
[8,42,303,2574,22128,175180,1231170,7652503, 42460424,212971589,977395362,4147719749, 16420984346,61103700814,215040758842,719522481940, 2299243641848,7043942786447,20758083457211, 59015575393057] |