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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 0 |
| 3 | 10 |
| 4 | 60 |
| 5 | 242 |
| 6 | 1032 |
| 7 | 4220 |
| 8 | 16376 |
| 9 | 62564 |
| 10 | 235728 |
| 11 | 875630 |
| 12 | 3220084 |
| 13 | 11746262 |
| 14 | 42545240 |
| 15 | 153181664 |
| 16 | 548710320 |
| 17 | 1956760904 |
| 18 | 6950669984 |
| 19 | 24604072658 |
| 20 | 86824376236 |
| 21 | 305540509370 |
| 22 | 1072522794920 |
| 23 | 3756266150212 |
| 24 | 13128230615656 |
[0,0,10,60,242,1032,4220,16376,62564,235728, 875630,3220084,11746262,42545240,153181664, 548710320,1956760904,6950669984,24604072658, 86824376236,305540509370,1072522794920, 3756266150212,13128230615656] |