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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 7 |
| 2 | 24 |
| 3 | 70 |
| 4 | 193 |
| 5 | 510 |
| 6 | 1304 |
| 7 | 3248 |
| 8 | 7920 |
| 9 | 18976 |
| 10 | 44800 |
| 11 | 104448 |
| 12 | 240896 |
| 13 | 550400 |
| 14 | 1247232 |
| 15 | 2805760 |
| 16 | 6270976 |
| 17 | 13934592 |
| 18 | 30801920 |
| 19 | 67764224 |
| 20 | 148439040 |
| 21 | 323878912 |
| 22 | 704118784 |
| 23 | 1525678080 |
| 24 | 3295674368 |
| 25 | 7098859520 |
| 26 | 15250489344 |
| 27 | 32682016768 |
| 28 | 69877104640 |
| 29 | 149082341376 |
[1,7,24,70,193,510,1304,3248,7920,18976,44800, 104448,240896,550400,1247232,2805760,6270976, 13934592,30801920,67764224,148439040,323878912, 704118784,1525678080,3295674368,7098859520, 15250489344,32682016768,69877104640,149082341376] |