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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 5 |
| 4 | 14 |
| 5 | 42 |
| 6 | 137 |
| 7 | 464 |
| 8 | 1626 |
| 9 | 5882 |
| 10 | 21677 |
| 11 | 81732 |
| 12 | 313304 |
| 13 | 1212616 |
| 14 | 4773498 |
| 15 | 18989434 |
| 16 | 75930374 |
| 17 | 307605618 |
| 18 | 1255603937 |
| 19 | 5139250646 |
| 20 | 21254360832 |
| 21 | 88416763064 |
| 22 | 368323147150 |
| 23 | 1547315926686 |
| 24 | 6531070849774 |
| 25 | 27584038509482 |
| 26 | 117317585175507 |
| 27 | 500936901965294 |
| 28 | 2139262376029736 |
[1,1,2,5,14,42,137,464,1626,5882,21677,81732, 313304,1212616,4773498,18989434,75930374, 307605618,1255603937,5139250646,21254360832, 88416763064,368323147150,1547315926686, 6531070849774,27584038509482,117317585175507, 500936901965294,2139262376029736] |