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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 0 |
| 2 | 1746 |
| 3 | 21456 |
| 4 | 147150 |
| 5 | 607536 |
| 6 | 2036334 |
| 7 | 5410800 |
| 8 | 13282866 |
| 9 | 27563184 |
| 10 | 56679732 |
| 11 | 102040272 |
| 12 | 184563384 |
| 13 | 302221728 |
| 14 | 504866340 |
| 15 | 763016400 |
| 16 | 1202127174 |
| 17 | 1728479808 |
| 18 | 2575653198 |
| 19 | 3561176016 |
| 20 | 5127122304 |
| 21 | 6797385072 |
| 22 | 9531403128 |
| 23 | 12329627616 |
| 24 | 16701654486 |
| 25 | 21199654080 |
[1,0,1746,21456,147150,607536,2036334,5410800, 13282866,27563184,56679732,102040272,184563384, 302221728,504866340,763016400,1202127174, 1728479808,2575653198,3561176016,5127122304, 6797385072,9531403128,12329627616,16701654486, 21199654080] |