| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 5 |
| 4 | 14 |
| 5 | 47 |
| 6 | 180 |
| 7 | 773 |
| 8 | 3701 |
| 9 | 19488 |
| 10 | 111890 |
| 11 | 695786 |
| 12 | 4656185 |
| 13 | 33356828 |
| 14 | 254675642 |
| 15 | 2063984616 |
| 16 | 17694054723 |
| 17 | 159958176316 |
| 18 | 1520689121858 |
| 19 | 15165205111010 |
[1,1,2,5,14,47,180,773,3701,19488,111890,695786, 4656185,33356828,254675642,2063984616,17694054723, 159958176316,1520689121858,15165205111010] |