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| n | a(n) |
|---|---|
| 1 | 2 |
| 2 | 16 |
| 3 | 52 |
| 4 | 428 |
| 5 | 1516 |
| 6 | 12792 |
| 7 | 46936 |
| 8 | 402164 |
| 9 | 1504432 |
| 10 | 13015480 |
| 11 | 49288856 |
| 12 | 429204354 |
| 13 | 1639174304 |
| 14 | 14340670000 |
| 15 | 55108565584 |
| 16 | 483825847108 |
| 17 | 1868067054968 |
| 18 | 16445659005424 |
| 19 | 63734526307552 |
| 20 | 562323306397388 |
| 21 | 2185849699156352 |
| 22 | 19320211642880176 |
| 23 | 75288454939134992 |
[2,16,52,428,1516,12792,46936,402164,1504432, 13015480,49288856,429204354,1639174304, 14340670000,55108565584,483825847108, 1868067054968,16445659005424,63734526307552, 562323306397388,2185849699156352, 19320211642880176,75288454939134992] |