| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 9 |
| 3 | 89 |
| 4 | 1105 |
| 5 | 16649 |
| 6 | 295561 |
| 7 | 6044737 |
| 8 | 139982529 |
| 9 | 3621002129 |
| 10 | 103486784401 |
| 11 | 3238428376721 |
| 12 | 110131633755793 |
| 13 | 4044369591078361 |
| 14 | 159505471943511513 |
| 15 | 6723976451270702849 |
| 16 | 301716313535065716481 |
| 17 | 14358232357247077816865 |
| 18 | 722298429807405401348641 |
[1,1,9,89,1105,16649,295561,6044737,139982529, 3621002129,103486784401,3238428376721, 110131633755793,4044369591078361, 159505471943511513,6723976451270702849, 301716313535065716481,14358232357247077816865, 722298429807405401348641] |