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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 2 |
| 4 | 8 |
| 5 | 28 |
| 6 | 152 |
| 7 | 952 |
| 8 | 7208 |
| 9 | 62296 |
| 10 | 605864 |
| 11 | 6522952 |
| 12 | 76951496 |
| 13 | 986411272 |
| 14 | 13647501224 |
| 15 | 202653304456 |
| 16 | 3214170659528 |
| 17 | 54223248489064 |
| 18 | 969422707369448 |
| 19 | 18308139748071496 |
| 20 | 364185707232235784 |
| 21 | 7610646121718276392 |
| 22 | 166694564791285014056 |
| 23 | 3818542633160305746952 |
[1,1,2,2,8,28,152,952,7208,62296,605864,6522952, 76951496,986411272,13647501224,202653304456, 3214170659528,54223248489064,969422707369448, 18308139748071496,364185707232235784, 7610646121718276392,166694564791285014056, 3818542633160305746952] |