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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 1 |
| 2 | 2 |
| 3 | 9 |
| 4 | 1000 |
| 5 | 1004006004001 |
| 6 | 1020191144865623440455270145683555422808365843606721760320032 |
[0,1,2,9,1000,1004006004001, 10201911448656234404552701456835554228083658436067\ 21760320032] |