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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 3 |
| 2 | 15 |
| 3 | 114 |
| 4 | 1152 |
| 5 | 14562 |
| 6 | 220842 |
| 7 | 3907656 |
| 8 | 79019496 |
| 9 | 1797660000 |
| 10 | 45439902288 |
| 11 | 1263456328032 |
| 12 | 38324061498672 |
| 13 | 1259345712721392 |
| 14 | 44565940575178992 |
| 15 | 1689757622095909248 |
| 16 | 68339921117338411776 |
| 17 | 2936658673480397537664 |
| 18 | 133615257668682429428352 |
| 19 | 6417113656859478628233984 |
| 20 | 324414161427519766056847104 |
[1,3,15,114,1152,14562,220842,3907656,79019496, 1797660000,45439902288,1263456328032, 38324061498672,1259345712721392,44565940575178992, 1689757622095909248,68339921117338411776, 2936658673480397537664,133615257668682429428352, 6417113656859478628233984, 324414161427519766056847104] |