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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 0 |
| 2 | 1 |
| 3 | 7 |
| 4 | 97 |
| 5 | 1561 |
| 6 | 41136 |
| 7 | 1551814 |
| 8 | 72440460 |
| 9 | 4281320257 |
| 10 | 324623105584 |
| 11 | 30086950057627 |
| 12 | 3299720918091511 |
| 13 | 428431079916572044 |
| 14 | 65637957066642609845 |
| 15 | 11659659637028895337265 |
| 16 | 2367270866164121777222596 |
| 17 | 546795407830461739380895161 |
| 18 | 143176487805296033192642234802 |
[1,0,1,7,97,1561,41136,1551814,72440460, 4281320257,324623105584,30086950057627, 3299720918091511,428431079916572044, 65637957066642609845,11659659637028895337265, 2367270866164121777222596, 546795407830461739380895161, 143176487805296033192642234802] |