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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 109 |
| 3 | 289 |
| 4 | 943 |
| 5 | 5121 |
| 6 | 21613 |
| 7 | 88177 |
| 8 | 387783 |
| 9 | 1670453 |
| 10 | 7119039 |
| 11 | 30633319 |
| 12 | 131658725 |
| 13 | 564682433 |
| 14 | 2424870987 |
| 15 | 10413508165 |
| 16 | 44703599613 |
| 17 | 191933847189 |
| 18 | 824103385305 |
| 19 | 3538210911515 |
| 20 | 15191170400903 |
| 21 | 65223636323455 |
[1,109,289,943,5121,21613,88177,387783,1670453, 7119039,30633319,131658725,564682433,2424870987, 10413508165,44703599613,191933847189,824103385305, 3538210911515,15191170400903,65223636323455] |