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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 6 |
| 4 | 21 |
| 5 | 73 |
| 6 | 240 |
| 7 | 744 |
| 8 | 2192 |
| 9 | 6192 |
| 10 | 16896 |
| 11 | 44800 |
| 12 | 115968 |
| 13 | 294144 |
| 14 | 733184 |
| 15 | 1800192 |
| 16 | 4362240 |
| 17 | 10448896 |
| 18 | 24772608 |
| 19 | 58195968 |
| 20 | 135593984 |
| 21 | 313589760 |
| 22 | 720371712 |
| 23 | 1644691456 |
| 24 | 3733979136 |
| 25 | 8433696768 |
| 26 | 18958254080 |
| 27 | 42429579264 |
| 28 | 94573166592 |
| 29 | 210000412672 |
| 30 | 464661774336 |
| 31 | 1024752353280 |
| 32 | 2252978782208 |
[1,1,2,6,21,73,240,744,2192,6192,16896,44800, 115968,294144,733184,1800192,4362240,10448896, 24772608,58195968,135593984,313589760,720371712, 1644691456,3733979136,8433696768,18958254080, 42429579264,94573166592,210000412672,464661774336, 1024752353280,2252978782208] |