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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 30 |
| 3 | 210 |
| 4 | 1290 |
| 5 | 7770 |
| 6 | 46650 |
| 7 | 279930 |
| 8 | 1679610 |
| 9 | 10077690 |
| 10 | 60466170 |
| 11 | 362797050 |
| 12 | 2176782330 |
| 13 | 13060694010 |
| 14 | 78364164090 |
| 15 | 470184984570 |
| 16 | 2821109907450 |
| 17 | 16926659444730 |
| 18 | 101559956668410 |
| 19 | 609359740010490 |
| 20 | 3656158440062970 |
| 21 | 21936950640377850 |
| 22 | 131621703842267130 |
[0,30,210,1290,7770,46650,279930,1679610,10077690, 60466170,362797050,2176782330,13060694010, 78364164090,470184984570,2821109907450, 16926659444730,101559956668410,609359740010490, 3656158440062970,21936950640377850, 131621703842267130] |