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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 0 |
| 3 | 0 |
| 4 | 2 |
| 5 | 0 |
| 6 | 6 |
| 7 | 8 |
| 8 | 24 |
| 9 | 60 |
| 10 | 148 |
| 11 | 396 |
| 12 | 1026 |
| 13 | 2744 |
| 14 | 7350 |
| 15 | 19872 |
| 16 | 54102 |
| 17 | 148104 |
| 18 | 407682 |
| 19 | 1127328 |
| 20 | 3130542 |
| 21 | 8726256 |
| 22 | 24407634 |
| 23 | 68482776 |
| 24 | 192698124 |
| 25 | 543642476 |
| 26 | 1537443024 |
| 27 | 4357677516 |
| 28 | 12376868254 |
| 29 | 35221087656 |
| 30 | 100409367690 |
| 31 | 286730523104 |
| 32 | 820078634232 |
| 33 | 2348966799132 |
[1,0,0,2,0,6,8,24,60,148,396,1026,2744,7350,19872, 54102,148104,407682,1127328,3130542,8726256, 24407634,68482776,192698124,543642476,1537443024, 4357677516,12376868254,35221087656,100409367690, 286730523104,820078634232,2348966799132] |