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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 1 |
| 3 | 2 |
| 4 | 4 |
| 5 | 9 |
| 6 | 20 |
| 7 | 47 |
| 8 | 112 |
| 9 | 273 |
| 10 | 677 |
| 11 | 1702 |
| 12 | 4330 |
| 13 | 11128 |
| 14 | 28847 |
| 15 | 75341 |
| 16 | 198066 |
| 17 | 523713 |
| 18 | 1391869 |
| 19 | 3716098 |
| 20 | 9962252 |
| 21 | 26806275 |
| 22 | 72372721 |
| 23 | 195994320 |
| 24 | 532266707 |
| 25 | 1449216287 |
| 26 | 3955193019 |
| 27 | 10818202369 |
| 28 | 29650108510 |
| 29 | 81417795070 |
| 30 | 223964216673 |
| 31 | 617097850848 |
| 32 | 1702943168118 |
[1,1,1,2,4,9,20,47,112,273,677,1702,4330,11128, 28847,75341,198066,523713,1391869,3716098,9962252, 26806275,72372721,195994320,532266707,1449216287, 3955193019,10818202369,29650108510,81417795070, 223964216673,617097850848,1702943168118] |