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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 0 |
| 2 | 0 |
| 3 | 1 |
| 4 | 4 |
| 5 | 12 |
| 6 | 29 |
| 7 | 71 |
| 8 | 186 |
| 9 | 468 |
| 10 | 1144 |
| 11 | 2718 |
| 12 | 6390 |
| 13 | 14920 |
| 14 | 34440 |
| 15 | 78720 |
| 16 | 178320 |
| 17 | 401088 |
| 18 | 896576 |
| 19 | 1992416 |
| 20 | 4404288 |
| 21 | 9689056 |
| 22 | 21223216 |
| 23 | 46305264 |
| 24 | 100663680 |
| 25 | 218104640 |
| 26 | 471104880 |
| 27 | 1014686160 |
| 28 | 2179696352 |
| 29 | 4670778048 |
| 30 | 9985801344 |
| 31 | 21303039648 |
| 32 | 45354855072 |
[0,0,0,1,4,12,29,71,186,468,1144,2718,6390,14920, 34440,78720,178320,401088,896576,1992416,4404288, 9689056,21223216,46305264,100663680,218104640, 471104880,1014686160,2179696352,4670778048, 9985801344,21303039648,45354855072] |