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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 4 |
| 4 | 9 |
| 5 | 20 |
| 6 | 45 |
| 7 | 102 |
| 8 | 232 |
| 9 | 528 |
| 10 | 1203 |
| 11 | 2742 |
| 12 | 6252 |
| 13 | 14258 |
| 14 | 32519 |
| 15 | 74173 |
| 16 | 169189 |
| 17 | 385929 |
| 18 | 880337 |
| 19 | 2008141 |
| 20 | 4580803 |
| 21 | 10449377 |
| 22 | 23836364 |
| 23 | 54373853 |
| 24 | 124033933 |
| 25 | 282937887 |
| 26 | 645419092 |
| 27 | 1472287344 |
| 28 | 3358484832 |
| 29 | 7661154644 |
| 30 | 17476122569 |
| 31 | 39865383333 |
| 32 | 90938296121 |
[1,1,2,4,9,20,45,102,232,528,1203,2742,6252,14258, 32519,74173,169189,385929,880337,2008141,4580803, 10449377,23836364,54373853,124033933,282937887, 645419092,1472287344,3358484832,7661154644, 17476122569,39865383333,90938296121] |