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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 8 |
| 3 | 84 |
| 4 | 1174 |
| 5 | 20680 |
| 6 | 440593 |
| 7 | 11024076 |
| 8 | 316969656 |
| 9 | 10299839283 |
| 10 | 373313501065 |
| 11 | 14932585789000 |
| 12 | 653449085198220 |
| 13 | 31053925215635803 |
| 14 | 1592721740865950464 |
| 15 | 87690229418143373920 |
| 16 | 5158511908430168388088 |
| 17 | 322910810936913397280700 |
| 18 | 21431596667884889101766973 |
[1,1,8,84,1174,20680,440593,11024076,316969656, 10299839283,373313501065,14932585789000, 653449085198220,31053925215635803, 1592721740865950464,87690229418143373920, 5158511908430168388088,322910810936913397280700, 21431596667884889101766973] |