The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 1 | 472 |
| 2 | 1626 |
| 3 | 7698 |
| 4 | 24696 |
| 5 | 89000 |
| 6 | 365308 |
| 7 | 1340176 |
| 8 | 4872072 |
| 9 | 18722120 |
| 10 | 70481648 |
| 11 | 261099100 |
| 12 | 983277524 |
| 13 | 3703246800 |
| 14 | 13842606580 |
| 15 | 51913534988 |
| 16 | 195076841960 |
| 17 | 731304173564 |
| 18 | 2741911934968 |
| 19 | 10290873860440 |
| 20 | 38603457828044 |
[472,1626,7698,24696,89000,365308,1340176,4872072, 18722120,70481648,261099100,983277524,3703246800, 13842606580,51913534988,195076841960,731304173564, 2741911934968,10290873860440,38603457828044] |