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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 4 |
| 2 | 62 |
| 3 | 1656 |
| 4 | 62476 |
| 5 | 3041200 |
| 6 | 181253256 |
| 7 | 12779289376 |
| 8 | 1040259450512 |
| 9 | 96008691963456 |
| 10 | 9906193528929760 |
| 11 | 1129945699713533824 |
| 12 | 141183268107518731968 |
| 13 | 19176614030629200880384 |
| 14 | 2813353012562289110458496 |
| 15 | 443345766248682440278848000 |
| 16 | 74687922008799389150557901056 |
[1,4,62,1656,62476,3041200,181253256,12779289376, 1040259450512,96008691963456,9906193528929760, 1129945699713533824,141183268107518731968, 19176614030629200880384,2813353012562289110458496, 443345766248682440278848000, 74687922008799389150557901056] |