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| n | a(n) |
|---|---|
| 1 | 120 |
| 2 | 276 |
| 3 | 1176 |
| 4 | 28920 |
| 5 | 126756 |
| 6 | 306936 |
| 7 | 1345620 |
| 8 | 33362196 |
| 9 | 146264856 |
| 10 | 354192420 |
| 11 | 1552832856 |
| 12 | 38499933816 |
| 13 | 168789505620 |
| 14 | 408737734296 |
| 15 | 1791967758756 |
| 16 | 44428890250020 |
| 17 | 194782943209176 |
| 18 | 471682991173716 |
| 19 | 2067929240760120 |
| 20 | 51270900848577816 |
| 21 | 224779347673872036 |
[120,276,1176,28920,126756,306936,1345620, 33362196,146264856,354192420,1552832856, 38499933816,168789505620,408737734296, 1791967758756,44428890250020,194782943209176, 471682991173716,2067929240760120, 51270900848577816,224779347673872036] |