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| n | a(n) |
|---|---|
| 1 | 4 |
| 2 | 10 |
| 3 | 74 |
| 4 | 548 |
| 5 | 29937 |
| 6 | 221207 |
| 7 | 12077476 |
| 8 | 89241150 |
| 9 | 4872401723 |
| 10 | 1965667148572 |
| 11 | 14524424832624 |
| 12 | 5859571186401306 |
| 13 | 319921746765027475 |
| 14 | 2363919734114673281 |
| 15 | 129065644309503369812 |
| 16 | 52068797165145438985917 |
| 17 | 21006052018952571274782967 |
| 18 | 155214896785095995435367107 |
[4,10,74,548,29937,221207,12077476,89241150, 4872401723,1965667148572,14524424832624, 5859571186401306,319921746765027475, 2363919734114673281,129065644309503369812, 52068797165145438985917, 21006052018952571274782967, 155214896785095995435367107] |