The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 1 | 20 |
| 2 | 88 |
| 3 | 292 |
| 4 | 988 |
| 5 | 3188 |
| 6 | 11140 |
| 7 | 39508 |
| 8 | 147892 |
| 9 | 562580 |
| 10 | 2191828 |
| 11 | 8605972 |
| 12 | 34091668 |
| 13 | 135464468 |
| 14 | 539959060 |
| 15 | 2154718228 |
| 16 | 8607898132 |
[20,88,292,988,3188,11140,39508,147892,562580, 2191828,8605972,34091668,135464468,539959060, 2154718228,8607898132] |