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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 3 |
| 3 | 10 |
| 4 | 30 |
| 5 | 98 |
| 6 | 323 |
| 7 | 1083 |
| 8 | 3684 |
| 9 | 12710 |
| 10 | 44272 |
| 11 | 155608 |
| 12 | 551259 |
| 13 | 1965952 |
| 14 | 7052990 |
| 15 | 25436711 |
| 16 | 92168542 |
| 17 | 335376653 |
| 18 | 1224991077 |
| 19 | 4489818110 |
| 20 | 16507728007 |
| 21 | 60868469848 |
| 22 | 225030777305 |
| 23 | 833961333273 |
| 24 | 3097594423724 |
| 25 | 11529400593846 |
| 26 | 42996077073284 |
| 27 | 160632616725238 |
| 28 | 601132116489719 |
| 29 | 2253153800577748 |
[1,1,3,10,30,98,323,1083,3684,12710,44272,155608, 551259,1965952,7052990,25436711,92168542, 335376653,1224991077,4489818110,16507728007, 60868469848,225030777305,833961333273, 3097594423724,11529400593846,42996077073284, 160632616725238,601132116489719,2253153800577748] |