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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 9 |
| 3 | 22 |
| 4 | 112 |
| 5 | 716 |
| 6 | 3100 |
| 7 | 14871 |
| 8 | 73900 |
| 9 | 349328 |
| 10 | 1679736 |
| 11 | 8094842 |
| 12 | 38736132 |
| 13 | 186037049 |
| 14 | 893328303 |
| 15 | 4285139965 |
| 16 | 20570385615 |
| 17 | 98729249057 |
| 18 | 473793905479 |
| 19 | 2274044573512 |
| 20 | 10914002589581 |
| 21 | 52379748049810 |
| 22 | 251394035040131 |
[0,9,22,112,716,3100,14871,73900,349328,1679736, 8094842,38736132,186037049,893328303,4285139965, 20570385615,98729249057,473793905479, 2274044573512,10914002589581,52379748049810, 251394035040131] |