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| n | a(n) |
|---|---|
| 1 | 8 |
| 2 | 36 |
| 3 | 200 |
| 4 | 1156 |
| 5 | 6728 |
| 6 | 39204 |
| 7 | 228488 |
| 8 | 1331716 |
| 9 | 7761800 |
| 10 | 45239076 |
| 11 | 263672648 |
| 12 | 1536796804 |
| 13 | 8957108168 |
| 14 | 52205852196 |
| 15 | 304278005000 |
| 16 | 1773462177796 |
| 17 | 10336495061768 |
| 18 | 60245508192804 |
| 19 | 351136554095048 |
| 20 | 2046573816377476 |
| 21 | 11928306344169800 |
[8,36,200,1156,6728,39204,228488,1331716,7761800, 45239076,263672648,1536796804,8957108168, 52205852196,304278005000,1773462177796, 10336495061768,60245508192804,351136554095048, 2046573816377476,11928306344169800] |