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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 2 |
| 3 | 2 |
| 4 | 6 |
| 5 | 10 |
| 6 | 22 |
| 7 | 38 |
| 8 | 82 |
| 9 | 154 |
| 10 | 318 |
| 11 | 614 |
| 12 | 1250 |
| 13 | 2462 |
| 14 | 4962 |
| 15 | 9842 |
| 16 | 19766 |
| 17 | 39378 |
| 18 | 78910 |
| 19 | 157502 |
| 20 | 315322 |
| 21 | 630030 |
| 22 | 1260674 |
| 23 | 2520098 |
| 24 | 5041446 |
| 25 | 10080430 |
| 26 | 20163322 |
| 27 | 40321682 |
| 28 | 80648326 |
| 29 | 161286810 |
| 30 | 322583462 |
| 31 | 645147158 |
| 32 | 1290314082 |
| 33 | 2580588786 |
| 34 | 5161216950 |
[0,2,2,6,10,22,38,82,154,318,614,1250,2462,4962, 9842,19766,39378,78910,157502,315322,630030, 1260674,2520098,5041446,10080430,20163322, 40321682,80648326,161286810,322583462,645147158, 1290314082,2580588786,5161216950] |