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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 21 |
| 3 | 402 |
| 4 | 7154 |
| 5 | 118863 |
| 6 | 2076117 |
| 7 | 37066859 |
| 8 | 666849212 |
| 9 | 12062165754 |
| 10 | 218944306666 |
| 11 | 3980414427158 |
| 12 | 72424065007263 |
| 13 | 1318344476372801 |
| 14 | 24003514023779867 |
| 15 | 437093903871650760 |
| 16 | 7959828410582705257 |
[1,21,402,7154,118863,2076117,37066859,666849212, 12062165754,218944306666,3980414427158, 72424065007263,1318344476372801,24003514023779867, 437093903871650760,7959828410582705257] |