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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 4 |
| 4 | 9 |
| 5 | 19 |
| 6 | 41 |
| 7 | 88 |
| 8 | 189 |
| 9 | 405 |
| 10 | 869 |
| 11 | 1864 |
| 12 | 3998 |
| 13 | 8575 |
| 14 | 18392 |
| 15 | 39448 |
| 16 | 84610 |
| 17 | 181475 |
| 18 | 389235 |
| 19 | 834848 |
| 20 | 1790617 |
| 21 | 3840591 |
| 22 | 8237462 |
| 23 | 17668057 |
| 24 | 37895195 |
| 25 | 81279216 |
| 26 | 174331098 |
| 27 | 373912708 |
| 28 | 801983781 |
| 29 | 1720128713 |
| 30 | 3689404772 |
| 31 | 7913191304 |
| 32 | 16972547194 |
| 33 | 36403436640 |
[1,1,2,4,9,19,41,88,189,405,869,1864,3998,8575, 18392,39448,84610,181475,389235,834848,1790617, 3840591,8237462,17668057,37895195,81279216, 174331098,373912708,801983781,1720128713, 3689404772,7913191304,16972547194,36403436640] |