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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 30 |
| 3 | 264 |
| 4 | 1140 |
| 5 | 3480 |
| 6 | 8610 |
| 7 | 18480 |
| 8 | 35784 |
| 9 | 64080 |
| 10 | 107910 |
| 11 | 172920 |
| 12 | 265980 |
| 13 | 395304 |
| 14 | 570570 |
| 15 | 803040 |
| 16 | 1105680 |
| 17 | 1493280 |
| 18 | 1982574 |
| 19 | 2592360 |
| 20 | 3343620 |
| 21 | 4259640 |
| 22 | 5366130 |
| 23 | 6691344 |
| 24 | 8266200 |
| 25 | 10124400 |
| 26 | 12302550 |
| 27 | 14840280 |
| 28 | 17780364 |
| 29 | 21168840 |
| 30 | 25055130 |
[0,30,264,1140,3480,8610,18480,35784,64080,107910, 172920,265980,395304,570570,803040,1105680, 1493280,1982574,2592360,3343620,4259640,5366130, 6691344,8266200,10124400,12302550,14840280, 17780364,21168840,25055130] |