| n | a(n) |
|---|---|
| 1 | 2 |
| 2 | 18 |
| 3 | 208 |
| 4 | 3730 |
| 5 | 201092 |
| 6 | 7335762 |
| 7 | 526460272 |
| 8 | 26465563878 |
| 9 | 2363769149128 |
| 10 | 487833920370774 |
| 11 | 40049421223880084 |
| 12 | 7972075784185713954 |
| 13 | 1235006486302921316794 |
| 14 | 124887894202756460238954 |
[2,18,208,3730,201092,7335762,526460272, 26465563878,2363769149128,487833920370774, 40049421223880084,7972075784185713954, 1235006486302921316794,124887894202756460238954] |