| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 2 |
| 4 | 5 |
| 5 | 13 |
| 6 | 49 |
| 7 | 169 |
| 8 | 972 |
| 9 | 5559 |
| 10 | 52979 |
| 11 | 526450 |
| 12 | 10617149 |
| 13 | 214475363 |
| 14 | 9035782113 |
| 15 | 476715641982 |
| 16 | 51820049305123 |
| 17 | 7479565064189887 |
| 18 | 2645418340373829359 |
| 19 | 1318520401609595443835 |
| 20 | 1774758704783778068230273 |
[1,1,2,5,13,49,169,972,5559,52979,526450,10617149, 214475363,9035782113,476715641982,51820049305123, 7479565064189887,2645418340373829359, 1318520401609595443835,1774758704783778068230273] |