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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 1 |
| 3 | 1 |
| 4 | 2 |
| 5 | 3 |
| 6 | 8 |
| 7 | 17 |
| 8 | 56 |
| 9 | 155 |
| 10 | 608 |
| 11 | 2073 |
| 12 | 9440 |
| 13 | 38227 |
| 14 | 198272 |
| 15 | 929569 |
| 16 | 5410688 |
| 17 | 28820619 |
| 18 | 186043904 |
| 19 | 1109652905 |
| 20 | 7867739648 |
| 21 | 51943281731 |
| 22 | 401293838336 |
| 23 | 2905151042481 |
| 24 | 24290513745920 |
| 25 | 191329672483963 |
| 26 | 1721379917619200 |
| 27 | 14655626154768697 |
| 28 | 141174819474169856 |
[1,1,1,1,2,3,8,17,56,155,608,2073,9440,38227, 198272,929569,5410688,28820619,186043904, 1109652905,7867739648,51943281731,401293838336, 2905151042481,24290513745920,191329672483963, 1721379917619200,14655626154768697, 141174819474169856] |