The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 0 | 2 |
| 1 | 15 |
| 2 | 117 |
| 3 | 945 |
| 4 | 7857 |
| 5 | 66825 |
| 6 | 578097 |
| 7 | 5062905 |
| 8 | 44726337 |
| 9 | 397498185 |
| 10 | 3547250577 |
| 11 | 31743856665 |
| 12 | 284606318817 |
| 13 | 2554926522345 |
| 14 | 22955156619057 |
| 15 | 206361317079225 |
| 16 | 1855841298759297 |
| 17 | 16694108359111305 |
| 18 | 150196195253667537 |
[2,15,117,945,7857,66825,578097,5062905,44726337, 397498185,3547250577,31743856665,284606318817, 2554926522345,22955156619057,206361317079225, 1855841298759297,16694108359111305, 150196195253667537] |