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| n | a(n) |
|---|---|
| 1 | 2 |
| 2 | 4 |
| 3 | 7 |
| 4 | 15 |
| 5 | 23 |
| 6 | 48 |
| 7 | 87 |
| 8 | 157 |
| 9 | 274 |
| 10 | 560 |
| 11 | 933 |
| 12 | 1822 |
| 13 | 3203 |
| 14 | 5993 |
| 15 | 10478 |
| 16 | 19922 |
| 17 | 34214 |
| 18 | 63331 |
| 19 | 110943 |
| 20 | 203812 |
| 21 | 352455 |
| 22 | 646274 |
| 23 | 1109722 |
| 24 | 2023785 |
| 25 | 3479398 |
| 26 | 6260690 |
| 27 | 10787932 |
| 28 | 19322649 |
| 29 | 33171504 |
| 30 | 59007624 |
| 31 | 100974521 |
| 32 | 179426764 |
| 33 | 306323274 |
[2,4,7,15,23,48,87,157,274,560,933,1822,3203,5993, 10478,19922,34214,63331,110943,203812,352455, 646274,1109722,2023785,3479398,6260690,10787932, 19322649,33171504,59007624,100974521,179426764, 306323274] |