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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 6 |
| 4 | 18 |
| 5 | 38 |
| 6 | 76 |
| 7 | 162 |
| 8 | 330 |
| 9 | 650 |
| 10 | 1272 |
| 11 | 2586 |
| 12 | 5262 |
| 13 | 10506 |
| 14 | 20856 |
| 15 | 41928 |
| 16 | 83684 |
| 17 | 165800 |
| 18 | 329310 |
| 19 | 653614 |
| 20 | 1303388 |
| 21 | 2584660 |
| 22 | 5139580 |
| 23 | 10210912 |
| 24 | 20288128 |
| 25 | 40224174 |
| 26 | 79824572 |
| 27 | 158316222 |
| 28 | 314272812 |
[1,1,2,6,18,38,76,162,330,650,1272,2586,5262, 10506,20856,41928,83684,165800,329310,653614, 1303388,2584660,5139580,10210912,20288128, 40224174,79824572,158316222,314272812] |