The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 1 | 16 |
| 2 | 72 |
| 3 | 516 |
| 4 | 3048 |
| 5 | 18944 |
| 6 | 115892 |
| 7 | 713488 |
| 8 | 4389504 |
| 9 | 26985196 |
| 10 | 165981072 |
| 11 | 1020610296 |
| 12 | 6276755004 |
| 13 | 38599285272 |
| 14 | 237374373944 |
| 15 | 1459772807380 |
| 16 | 8977123838008 |
| 17 | 55206398795888 |
| 18 | 339501216593668 |
| 19 | 2087821797237664 |
[16,72,516,3048,18944,115892,713488,4389504, 26985196,165981072,1020610296,6276755004, 38599285272,237374373944,1459772807380, 8977123838008,55206398795888,339501216593668, 2087821797237664] |