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| n | a(n) |
|---|---|
| 0 | 2 |
| 1 | 3 |
| 2 | 4 |
| 3 | 8 |
| 4 | 20 |
| 5 | 44 |
| 6 | 92 |
| 7 | 188 |
| 8 | 380 |
| 9 | 856 |
| 10 | 2148 |
| 11 | 5024 |
| 12 | 17616 |
| 13 | 58768 |
| 14 | 176320 |
| 15 | 755904 |
| 16 | 3305920 |
| 17 | 13885184 |
| 18 | 69634816 |
| 19 | 348174336 |
| 20 | 2385273856 |
| 21 | 14652403712 |
| 22 | 102566830080 |
| 23 | 849285738496 |
| 24 | 6035962949632 |
| 25 | 44017806979072 |
| 26 | 308166534991872 |
| 27 | 2380768960708608 |
| 28 | 23410894780694528 |
[2,3,4,8,20,44,92,188,380,856,2148,5024,17616, 58768,176320,755904,3305920,13885184,69634816, 348174336,2385273856,14652403712,102566830080, 849285738496,6035962949632,44017806979072, 308166534991872,2380768960708608, 23410894780694528] |