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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 3 |
| 3 | 10 |
| 4 | 51 |
| 5 | 286 |
| 6 | 1710 |
| 7 | 10740 |
| 8 | 69763 |
| 9 | 464822 |
| 10 | 3159450 |
| 11 | 21821516 |
| 12 | 152708078 |
| 13 | 1080452972 |
| 14 | 7716009724 |
| 15 | 55545950568 |
| 16 | 402649640163 |
| 17 | 2936600795174 |
| 18 | 21532660592418 |
| 19 | 158645924209500 |
| 20 | 1173875395710458 |
| 21 | 8719519396134596 |
| 22 | 64995349923442628 |
| 23 | 486020221692290392 |
[1,3,10,51,286,1710,10740,69763,464822,3159450, 21821516,152708078,1080452972,7716009724, 55545950568,402649640163,2936600795174, 21532660592418,158645924209500,1173875395710458, 8719519396134596,64995349923442628, 486020221692290392] |