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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 3 |
| 3 | 9 |
| 4 | 35 |
| 5 | 147 |
| 6 | 710 |
| 7 | 3780 |
| 8 | 21391 |
| 9 | 136063 |
| 10 | 932190 |
| 11 | 6887232 |
| 12 | 55902274 |
| 13 | 497726270 |
| 14 | 4711586833 |
| 15 | 47692742905 |
| 16 | 528539419087 |
| 17 | 6093676850975 |
| 18 | 73010887114406 |
| 19 | 943925266298096 |
| 20 | 12740929019736310 |
| 21 | 175037826035276730 |
| 22 | 2561985529052306447 |
| 23 | 39817440376814520907 |
| 24 | 622315443336146270858 |
[1,1,3,9,35,147,710,3780,21391,136063,932190, 6887232,55902274,497726270,4711586833,47692742905, 528539419087,6093676850975,73010887114406, 943925266298096,12740929019736310, 175037826035276730,2561985529052306447, 39817440376814520907,622315443336146270858] |