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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 10 |
| 3 | 210 |
| 4 | 5505 |
| 5 | 161601 |
| 6 | 5082420 |
| 7 | 167451780 |
| 8 | 5705082795 |
| 9 | 199354509755 |
| 10 | 7105393162010 |
| 11 | 257312347583330 |
| 12 | 9440808323869455 |
| 13 | 350189693739455535 |
| 14 | 13110655796699158800 |
| 15 | 494772468434359266960 |
| 16 | 18801468275832345890970 |
[1,1,10,210,5505,161601,5082420,167451780, 5705082795,199354509755,7105393162010, 257312347583330,9440808323869455, 350189693739455535,13110655796699158800, 494772468434359266960,18801468275832345890970] |