The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 2 |
| 3 | 11 |
| 4 | 19 |
| 5 | 20 |
| 6 | 74 |
| 7 | 398 |
| 8 | 779 |
| 9 | 1062 |
| 10 | 2329 |
| 11 | 4189 |
| 12 | 4280 |
| 13 | 11278 |
| 14 | 19962 |
| 15 | 98318 |
| 16 | 135137 |
| 17 | 1051360 |
| 18 | 1592930 |
| 19 | 69226926 |
| 20 | 4295054186 |
| 21 | 4446008678 |
| 22 | 17187271449 |
| 23 | 18123849698 |
[0,2,11,19,20,74,398,779,1062,2329,4189,4280, 11278,19962,98318,135137,1051360,1592930,69226926, 4295054186,4446008678,17187271449,18123849698] |