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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 6 |
| 3 | 21 |
| 4 | 83 |
| 5 | 349 |
| 6 | 1528 |
| 7 | 6885 |
| 8 | 31663 |
| 9 | 147881 |
| 10 | 698854 |
| 11 | 3333119 |
| 12 | 16013223 |
| 13 | 77383680 |
| 14 | 375742768 |
| 15 | 1831622869 |
| 16 | 8957731740 |
| 17 | 43928634211 |
| 18 | 215923994375 |
| 19 | 1063428003467 |
| 20 | 5246221788939 |
| 21 | 25918820316508 |
| 22 | 128212232578680 |
| 23 | 634919400291523 |
| 24 | 3147189891410274 |
| 25 | 15613197779383373 |
| 26 | 77514351786069528 |
[1,2,6,21,83,349,1528,6885,31663,147881,698854, 3333119,16013223,77383680,375742768,1831622869, 8957731740,43928634211,215923994375,1063428003467, 5246221788939,25918820316508,128212232578680, 634919400291523,3147189891410274, 15613197779383373,77514351786069528] |