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| n | a(n) |
|---|---|
| 1 | 2 |
| 2 | 8 |
| 3 | 30 |
| 4 | 102 |
| 5 | 348 |
| 6 | 1172 |
| 7 | 3956 |
| 8 | 13326 |
| 9 | 44916 |
| 10 | 151338 |
| 11 | 509978 |
| 12 | 1718408 |
| 13 | 5790456 |
| 14 | 19511640 |
| 15 | 65747178 |
| 16 | 221543696 |
| 17 | 746521190 |
| 18 | 2515502046 |
| 19 | 8476319172 |
| 20 | 28562083692 |
| 21 | 96243740012 |
| 22 | 324306077270 |
| 23 | 1092792451740 |
| 24 | 3682309466130 |
| 25 | 12408031373682 |
[2,8,30,102,348,1172,3956,13326,44916,151338, 509978,1718408,5790456,19511640,65747178, 221543696,746521190,2515502046,8476319172, 28562083692,96243740012,324306077270, 1092792451740,3682309466130,12408031373682] |