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| n | a(n) |
|---|---|
| 1 | 2 |
| 2 | 4 |
| 3 | 9 |
| 4 | 18 |
| 5 | 36 |
| 6 | 71 |
| 7 | 140 |
| 8 | 276 |
| 9 | 545 |
| 10 | 1078 |
| 11 | 2136 |
| 12 | 4239 |
| 13 | 8424 |
| 14 | 16760 |
| 15 | 33377 |
| 16 | 66522 |
| 17 | 132668 |
| 18 | 264727 |
| 19 | 528468 |
| 20 | 1055340 |
| 21 | 2108097 |
| 22 | 4212014 |
| 23 | 8417264 |
| 24 | 16823583 |
| 25 | 33629456 |
| 26 | 67230256 |
| 27 | 134414145 |
| 28 | 268753266 |
| 29 | 537385140 |
| 30 | 1074573863 |
| 31 | 2148829916 |
| 32 | 4297145604 |
| 33 | 8593459169 |
[2,4,9,18,36,71,140,276,545,1078,2136,4239,8424, 16760,33377,66522,132668,264727,528468,1055340, 2108097,4212014,8417264,16823583,33629456, 67230256,134414145,268753266,537385140,1074573863, 2148829916,4297145604,8593459169] |