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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 6 |
| 3 | 23 |
| 4 | 94 |
| 5 | 392 |
| 6 | 1680 |
| 7 | 7387 |
| 8 | 33110 |
| 9 | 150905 |
| 10 | 698996 |
| 11 | 3287550 |
| 12 | 15685420 |
| 13 | 75877427 |
| 14 | 371994692 |
| 15 | 1847450970 |
| 16 | 9290557158 |
| 17 | 47291312897 |
| 18 | 243574276884 |
| 19 | 1268915237141 |
| 20 | 6683909556420 |
| 21 | 35585631836229 |
| 22 | 191433293140656 |
| 23 | 1040197718292138 |
| 24 | 5707318227692796 |
[1,2,6,23,94,392,1680,7387,33110,150905,698996, 3287550,15685420,75877427,371994692,1847450970, 9290557158,47291312897,243574276884,1268915237141, 6683909556420,35585631836229,191433293140656, 1040197718292138,5707318227692796] |