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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 5 |
| 3 | 16 |
| 4 | 65 |
| 5 | 326 |
| 6 | 1957 |
| 7 | 13700 |
| 8 | 109601 |
| 9 | 986410 |
| 10 | 9864101 |
| 11 | 108505112 |
| 12 | 1302061345 |
| 13 | 16926797486 |
| 14 | 236975164805 |
| 15 | 3554627472076 |
| 16 | 56874039553217 |
| 17 | 966858672404690 |
| 18 | 17403456103284421 |
| 19 | 330665665962404000 |
| 20 | 6613313319248080001 |
| 21 | 138879579704209680022 |
| 22 | 3055350753492612960485 |
| 23 | 70273067330330098091156 |
[1,2,5,16,65,326,1957,13700,109601,986410,9864101, 108505112,1302061345,16926797486,236975164805, 3554627472076,56874039553217,966858672404690, 17403456103284421,330665665962404000, 6613313319248080001,138879579704209680022, 3055350753492612960485,70273067330330098091156] |