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A228080 as a simple table
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2520 |
| 2 | 7484400 |
| 3 | 22870848000 |
| 4 | 70579794285000 |
| 5 | 218799620836917120 |
| 6 | 679953587124305894400 |
| 7 | 2116187746296592370688000 |
| 8 | 6592431144164903462359935000 |
| 9 | 20550499897066845200729434200000 |
| 10 | 64091912654977017603465324370118400 |
| 11 | 199956261330234671205699024876891648000 |
[1,2520,7484400,22870848000,70579794285000, 218799620836917120,679953587124305894400, 2116187746296592370688000, 6592431144164903462359935000, 20550499897066845200729434200000, 64091912654977017603465324370118400, 199956261330234671205699024876891648000] |