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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 4 |
| 2 | 10 |
| 3 | 32 |
| 4 | 119 |
| 5 | 468 |
| 6 | 1934 |
| 7 | 8256 |
| 8 | 36135 |
| 9 | 161276 |
| 10 | 731158 |
| 11 | 3357748 |
| 12 | 15587004 |
| 13 | 73021200 |
| 14 | 344786056 |
| 15 | 1639145180 |
| 16 | 7839483967 |
| 17 | 37692820908 |
| 18 | 182087119582 |
| 19 | 883358016328 |
| 20 | 4301799946048 |
| 21 | 21021519618724 |
| 22 | 103049029114618 |
| 23 | 506608410994868 |
| 24 | 2497162797380145 |
| 25 | 12338908560964968 |
[1,4,10,32,119,468,1934,8256,36135,161276,731158, 3357748,15587004,73021200,344786056,1639145180, 7839483967,37692820908,182087119582,883358016328, 4301799946048,21021519618724,103049029114618, 506608410994868,2497162797380145, 12338908560964968] |