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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 10 |
| 3 | 40 |
| 4 | 192 |
| 5 | 840 |
| 6 | 4136 |
| 7 | 19072 |
| 8 | 93984 |
| 9 | 443200 |
| 10 | 2197056 |
| 11 | 10529408 |
| 12 | 52254080 |
| 13 | 252754560 |
| 14 | 1257233536 |
| 15 | 6125430784 |
| 16 | 30490513920 |
| 17 | 149263315968 |
| 18 | 743819838464 |
| 19 | 3655479169024 |
| 20 | 18224641949696 |
| 21 | 89813644283904 |
| 22 | 448049879896064 |
| 23 | 2213201659002880 |
| 24 | 11044272618651648 |
| 25 | 54650659023355904 |
| 26 | 272818438753746944 |
[1,2,10,40,192,840,4136,19072,93984,443200, 2197056,10529408,52254080,252754560,1257233536, 6125430784,30490513920,149263315968,743819838464, 3655479169024,18224641949696,89813644283904, 448049879896064,2213201659002880, 11044272618651648,54650659023355904, 272818438753746944] |