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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 0 |
| 2 | 9396 |
| 3 | 284528 |
| 4 | 3309660 |
| 5 | 21996036 |
| 6 | 103632480 |
| 7 | 384538752 |
| 8 | 1195104618 |
| 9 | 3253783500 |
| 10 | 7971340896 |
| 11 | 17905302720 |
| 12 | 37530681590 |
| 13 | 74139276672 |
| 14 | 139067432280 |
| 15 | 250102136592 |
| 16 | 433070833500 |
| 17 | 724358442744 |
| 18 | 1178016364548 |
| 19 | 1866143480400 |
| 20 | 2883345017508 |
| 21 | 4367172766500 |
[1,0,9396,284528,3309660,21996036,103632480, 384538752,1195104618,3253783500,7971340896, 17905302720,37530681590,74139276672,139067432280, 250102136592,433070833500,724358442744, 1178016364548,1866143480400,2883345017508, 4367172766500] |