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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 0 |
| 2 | 30 |
| 3 | 200 |
| 4 | 570 |
| 5 | 1392 |
| 6 | 3020 |
| 7 | 5280 |
| 8 | 9090 |
| 9 | 15040 |
| 10 | 22272 |
| 11 | 33480 |
| 12 | 47540 |
| 13 | 63120 |
| 14 | 86400 |
| 15 | 113184 |
| 16 | 146610 |
| 17 | 191040 |
| 18 | 238330 |
| 19 | 296520 |
| 20 | 358752 |
[1,0,30,200,570,1392,3020,5280,9090,15040,22272, 33480,47540,63120,86400,113184,146610,191040, 238330,296520,358752] |