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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 4 |
| 4 | 12 |
| 5 | 30 |
| 6 | 89 |
| 7 | 264 |
| 8 | 884 |
| 9 | 2747 |
| 10 | 9329 |
| 11 | 31445 |
| 12 | 112592 |
| 13 | 386695 |
| 14 | 1404984 |
| 15 | 5055108 |
| 16 | 18900644 |
| 17 | 68752713 |
| 18 | 260143007 |
| 19 | 974793598 |
| 20 | 3755514208 |
| 21 | 14179006578 |
| 22 | 55137620398 |
| 23 | 212489097664 |
| 24 | 836744112593 |
| 25 | 3242710398416 |
| 26 | 12862836044126 |
| 27 | 50605909221367 |
| 28 | 202622230548568 |
| 29 | 800607178797359 |
| 30 | 3224291827647012 |
[1,1,2,4,12,30,89,264,884,2747,9329,31445,112592, 386695,1404984,5055108,18900644,68752713, 260143007,974793598,3755514208,14179006578, 55137620398,212489097664,836744112593, 3242710398416,12862836044126,50605909221367, 202622230548568,800607178797359,3224291827647012] |