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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 7 |
| 3 | 39 |
| 4 | 242 |
| 5 | 1634 |
| 6 | 11631 |
| 7 | 85957 |
| 8 | 653245 |
| 9 | 5072862 |
| 10 | 40077807 |
| 11 | 321106623 |
| 12 | 2602911282 |
| 13 | 21308131235 |
| 14 | 175909559897 |
| 15 | 1462846379247 |
| 16 | 12242600576066 |
| 17 | 103035285071630 |
| 18 | 871490142773640 |
| 19 | 7404121610615520 |
| 20 | 63157400073057627 |
| 21 | 540689217572662413 |
| 22 | 4644083121177225292 |
[1,2,7,39,242,1634,11631,85957,653245,5072862, 40077807,321106623,2602911282,21308131235, 175909559897,1462846379247,12242600576066, 103035285071630,871490142773640,7404121610615520, 63157400073057627,540689217572662413, 4644083121177225292] |