The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 2 |
| 3 | 8 |
| 4 | 41 |
| 5 | 249 |
| 6 | 1754 |
| 7 | 14084 |
| 8 | 127057 |
| 9 | 1272625 |
| 10 | 14015014 |
| 11 | 168323364 |
| 12 | 2189619553 |
| 13 | 30670104577 |
| 14 | 460235322854 |
| 15 | 7366138539416 |
| 16 | 125257398648401 |
| 17 | 2255126454472401 |
| 18 | 42855262052316218 |
| 19 | 857238357862313360 |
[1,2,8,41,249,1754,14084,127057,1272625,14015014, 168323364,2189619553,30670104577,460235322854, 7366138539416,125257398648401,2255126454472401, 42855262052316218,857238357862313360] |