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| n | a(n) |
|---|---|
| 2 | 1 |
| 3 | 3 |
| 4 | 9 |
| 5 | 30 |
| 6 | 103 |
| 7 | 359 |
| 8 | 1288 |
| 9 | 4689 |
| 10 | 17314 |
| 11 | 64534 |
| 12 | 242041 |
| 13 | 913736 |
| 14 | 3467291 |
| 15 | 13218109 |
| 16 | 50584796 |
| 17 | 194187685 |
| 18 | 747554181 |
| 19 | 2884909591 |
| 20 | 11157920117 |
| 21 | 43240538732 |
| 22 | 167862452804 |
| 23 | 652673851739 |
| 24 | 2541286908281 |
| 25 | 9907679984365 |
| 26 | 38672555616984 |
| 27 | 151112970258915 |
| 28 | 591058042101783 |
[1,3,9,30,103,359,1288,4689,17314,64534,242041, 913736,3467291,13218109,50584796,194187685, 747554181,2884909591,11157920117,43240538732, 167862452804,652673851739,2541286908281, 9907679984365,38672555616984,151112970258915, 591058042101783] |