| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 7 |
| 3 | 74 |
| 4 | 1060 |
| 5 | 19013 |
| 6 | 408650 |
| 7 | 10219360 |
| 8 | 291158230 |
| 9 | 9302358947 |
| 10 | 329192040880 |
| 11 | 12775809098058 |
| 12 | 539351216354728 |
| 13 | 24600280965461923 |
| 14 | 1205263251360664310 |
| 15 | 63115789721408960624 |
| 16 | 3517483455875467926588 |
| 17 | 207834769804597591153769 |
| 18 | 12976002600530598793672490 |
[1,1,7,74,1060,19013,408650,10219360,291158230, 9302358947,329192040880,12775809098058, 539351216354728,24600280965461923, 1205263251360664310,63115789721408960624, 3517483455875467926588,207834769804597591153769, 12976002600530598793672490] |