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| n | a(n) |
|---|---|
| 1 | 28 |
| 2 | 236 |
| 3 | 2280 |
| 4 | 20836 |
| 5 | 202264 |
| 6 | 1851020 |
| 7 | 17970056 |
| 8 | 164457412 |
| 9 | 1596586328 |
| 10 | 14611562156 |
| 11 | 141852049992 |
| 12 | 1298194798372 |
| 13 | 12603142057880 |
| 14 | 115340831992268 |
| 15 | 1119752515193608 |
| 16 | 10247697449986948 |
| 17 | 99486754138704856 |
| 18 | 910478112673392620 |
[28,236,2280,20836,202264,1851020,17970056, 164457412,1596586328,14611562156,141852049992, 1298194798372,12603142057880,115340831992268, 1119752515193608,10247697449986948, 99486754138704856,910478112673392620] |