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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 0 |
| 3 | 2 |
| 4 | 2 |
| 5 | 4 |
| 6 | 10 |
| 7 | 18 |
| 8 | 36 |
| 9 | 74 |
| 10 | 146 |
| 11 | 292 |
| 12 | 586 |
| 13 | 1170 |
| 14 | 2340 |
| 15 | 4682 |
| 16 | 9362 |
| 17 | 18724 |
| 18 | 37450 |
| 19 | 74898 |
| 20 | 149796 |
| 21 | 299594 |
| 22 | 599186 |
| 23 | 1198372 |
| 24 | 2396746 |
| 25 | 4793490 |
| 26 | 9586980 |
| 27 | 19173962 |
| 28 | 38347922 |
| 29 | 76695844 |
| 30 | 153391690 |
| 31 | 306783378 |
| 32 | 613566756 |
| 33 | 1227133514 |
| 34 | 2454267026 |
| 35 | 4908534052 |
[0,0,2,2,4,10,18,36,74,146,292,586,1170,2340,4682, 9362,18724,37450,74898,149796,299594,599186, 1198372,2396746,4793490,9586980,19173962,38347922, 76695844,153391690,306783378,613566756,1227133514, 2454267026,4908534052] |