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| n | a(n) |
|---|---|
| 1 | 81 |
| 2 | 171 |
| 3 | 361 |
| 4 | 855 |
| 5 | 2025 |
| 6 | 5175 |
| 7 | 13225 |
| 8 | 35535 |
| 9 | 95481 |
| 10 | 265431 |
| 11 | 737881 |
| 12 | 2100255 |
| 13 | 5978025 |
| 14 | 17298375 |
| 15 | 50055625 |
| 16 | 146516175 |
| 17 | 428862681 |
| 18 | 1265299191 |
| 19 | 3733087801 |
| 20 | 11073888255 |
| 21 | 32849750025 |
| 22 | 97806145575 |
| 23 | 291205933225 |
| 24 | 869194951215 |
[81,171,361,855,2025,5175,13225,35535,95481, 265431,737881,2100255,5978025,17298375,50055625, 146516175,428862681,1265299191,3733087801, 11073888255,32849750025,97806145575,291205933225, 869194951215] |