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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 4 |
| 4 | 10 |
| 5 | 23 |
| 6 | 63 |
| 7 | 155 |
| 8 | 448 |
| 9 | 1151 |
| 10 | 3450 |
| 11 | 9137 |
| 12 | 28134 |
| 13 | 76236 |
| 14 | 239712 |
| 15 | 661374 |
| 16 | 2115046 |
| 17 | 5921549 |
| 18 | 19203568 |
| 19 | 54422726 |
| 20 | 178585838 |
| 21 | 511343777 |
| 22 | 1694965469 |
| 23 | 4896195579 |
| 24 | 16371992897 |
| 25 | 47656781437 |
| 26 | 160578870274 |
| 27 | 470571482142 |
| 28 | 1596323368095 |
| 29 | 4705798878362 |
| 30 | 16059653893209 |
[1,1,2,4,10,23,63,155,448,1151,3450,9137,28134, 76236,239712,661374,2115046,5921549,19203568, 54422726,178585838,511343777,1694965469, 4896195579,16371992897,47656781437,160578870274, 470571482142,1596323368095,4705798878362, 16059653893209] |