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| n | a(n) |
|---|---|
| 1 | 72 |
| 2 | 560 |
| 3 | 3240 |
| 4 | 19584 |
| 5 | 99096 |
| 6 | 540368 |
| 7 | 2598040 |
| 8 | 13521264 |
| 9 | 64019304 |
| 10 | 326134032 |
| 11 | 1542290552 |
| 12 | 7781321872 |
[72,560,3240,19584,99096,540368,2598040,13521264, 64019304,326134032,1542290552,7781321872] |