| n | a(n) |
|---|---|
| 12 | 1 |
| 13 | 13421773 |
| 14 | 240191982810781 |
| 15 | 3967756584209486471005 |
| 16 | 66828959857649638516515454045 |
| 17 | 1120110037194182450025632158559979613 |
| 18 | 18796917128597217472986991275660647159371869 |
[1,13421773,240191982810781, 3967756584209486471005, 66828959857649638516515454045, 1120110037194182450025632158559979613, 18796917128597217472986991275660647159371869] |