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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 4 |
| 3 | 16 |
| 4 | 46 |
| 5 | 128 |
| 6 | 332 |
| 7 | 842 |
| 8 | 2042 |
| 9 | 4846 |
| 10 | 11146 |
| 11 | 25114 |
| 12 | 55310 |
| 13 | 119662 |
| 14 | 254354 |
| 15 | 532784 |
| 16 | 1100411 |
| 17 | 2245118 |
| 18 | 4528212 |
| 19 | 9038898 |
| 20 | 17868025 |
| 21 | 35006932 |
| 22 | 68008606 |
| 23 | 131083778 |
| 24 | 250774482 |
| 25 | 476372848 |
| 26 | 898837825 |
| 27 | 1685107392 |
| 28 | 3139812791 |
| 29 | 5816015908 |
| 30 | 10712596279 |
| 31 | 19625001436 |
| 32 | 35765137033 |
| 33 | 64853219808 |
| 34 | 117031972499 |
| 35 | 210211082354 |
| 36 | 375886565558 |
| 37 | 669232663688 |
| 38 | 1186538314110 |
| 39 | 2095236499224 |
| 40 | 3685445929502 |
[1,4,16,46,128,332,842,2042,4846,11146,25114, 55310,119662,254354,532784,1100411,2245118, 4528212,9038898,17868025,35006932,68008606, 131083778,250774482,476372848,898837825, 1685107392,3139812791,5816015908,10712596279, 19625001436,35765137033,64853219808,117031972499, 210211082354,375886565558,669232663688, 1186538314110,2095236499224,3685445929502] |