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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 7 |
| 3 | 24 |
| 4 | 98 |
| 5 | 407 |
| 6 | 1740 |
| 7 | 7626 |
| 8 | 34019 |
| 9 | 154027 |
| 10 | 702375 |
| 11 | 3238330 |
| 12 | 15036002 |
| 13 | 70193322 |
| 14 | 329372882 |
| 15 | 1552973839 |
| 16 | 7351786503 |
| 17 | 34904153493 |
| 18 | 166258508011 |
| 19 | 794139913006 |
| 20 | 3802027819251 |
| 21 | 18240300341080 |
| 22 | 87689544587124 |
| 23 | 422337692525636 |
| 24 | 2037180422979907 |
| 25 | 9841473054662320 |
| 26 | 47610988497196482 |
| 27 | 230621686993480390 |
[1,2,7,24,98,407,1740,7626,34019,154027,702375, 3238330,15036002,70193322,329372882,1552973839, 7351786503,34904153493,166258508011,794139913006, 3802027819251,18240300341080,87689544587124, 422337692525636,2037180422979907,9841473054662320, 47610988497196482,230621686993480390] |