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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 0 |
| 2 | 2 |
| 3 | 2 |
| 4 | 10 |
| 5 | 22 |
| 6 | 82 |
| 7 | 220 |
| 8 | 808 |
| 9 | 2356 |
| 10 | 8656 |
| 11 | 26654 |
| 12 | 98102 |
| 13 | 312984 |
| 14 | 1156032 |
| 15 | 3782616 |
| 16 | 14015132 |
| 17 | 46756952 |
| 18 | 173680748 |
| 19 | 588380312 |
| 20 | 2190211648 |
| 21 | 7512444672 |
| 22 | 28014835088 |
| 23 | 97081546938 |
| 24 | 362582983586 |
| 25 | 1267349177760 |
| 26 | 4739583478208 |
| 27 | 16688334026768 |
| 28 | 62482287911704 |
| 29 | 221396939695828 |
| 30 | 829766494964876 |
| 31 | 2956346830527760 |
[1,0,2,2,10,22,82,220,808,2356,8656,26654,98102, 312984,1156032,3782616,14015132,46756952, 173680748,588380312,2190211648,7512444672, 28014835088,97081546938,362582983586, 1267349177760,4739583478208,16688334026768, 62482287911704,221396939695828,829766494964876, 2956346830527760] |