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| n | a(n) |
|---|---|
| 1 | 3 |
| 2 | 6 |
| 3 | 20 |
| 4 | 80 |
| 5 | 576 |
| 6 | 4608 |
| 7 | 69632 |
| 8 | 1114112 |
| 9 | 34603008 |
| 10 | 1107296256 |
| 11 | 69793218560 |
| 12 | 4466765987840 |
| 13 | 567347999932416 |
| 14 | 72620543991349248 |
| 15 | 18518801667747479552 |
| 16 | 4740813226943354765312 |
| 17 | 2422574005712127994626048 |
[3,6,20,80,576,4608,69632,1114112,34603008, 1107296256,69793218560,4466765987840, 567347999932416,72620543991349248, 18518801667747479552,4740813226943354765312, 2422574005712127994626048] |