| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 13 |
| 3 | 320 |
| 4 | 1085 |
| 5 | 5108 |
| 6 | 50127 |
| 7 | 431723 |
| 8 | 2741816 |
| 9 | 19713343 |
| 10 | 158831909 |
| 11 | 1226649472 |
| 12 | 9140274733 |
| 13 | 69805274732 |
| 14 | 540678554646 |
| 15 | 4154873500103 |
| 16 | 31813469310773 |
| 17 | 244579087519367 |
| 18 | 1883206579435015 |
| 19 | 14482216168483555 |
| 20 | 111339711139069346 |
[1,13,320,1085,5108,50127,431723,2741816,19713343, 158831909,1226649472,9140274733,69805274732, 540678554646,4154873500103,31813469310773, 244579087519367,1883206579435015, 14482216168483555,111339711139069346] |