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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 7 |
| 3 | 27 |
| 4 | 116 |
| 5 | 497 |
| 6 | 2232 |
| 7 | 10122 |
| 8 | 46820 |
| 9 | 217378 |
| 10 | 1022711 |
| 11 | 4830705 |
| 12 | 22970740 |
| 13 | 109584144 |
| 14 | 525462784 |
| 15 | 2525499776 |
| 16 | 12177778554 |
| 17 | 58848262607 |
| 18 | 285083921385 |
| 19 | 1383267877806 |
| 20 | 6724508075801 |
| 21 | 32736970796288 |
| 22 | 159603849456491 |
| 23 | 779020488726563 |
| 24 | 3806960296642761 |
| 25 | 18622509529297549 |
| 26 | 91183505657071124 |
[1,2,7,27,116,497,2232,10122,46820,217378,1022711, 4830705,22970740,109584144,525462784,2525499776, 12177778554,58848262607,285083921385, 1383267877806,6724508075801,32736970796288, 159603849456491,779020488726563,3806960296642761, 18622509529297549,91183505657071124] |