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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 30 |
| 3 | 270 |
| 4 | 1400 |
| 5 | 5250 |
| 6 | 15876 |
| 7 | 41160 |
| 8 | 95040 |
| 9 | 200475 |
| 10 | 393250 |
| 11 | 726726 |
| 12 | 1277640 |
| 13 | 2153060 |
| 14 | 3498600 |
| 15 | 5508000 |
| 16 | 8434176 |
| 17 | 12601845 |
| 18 | 18421830 |
| 19 | 26407150 |
| 20 | 37191000 |
| 21 | 51546726 |
| 22 | 70409900 |
| 23 | 94902600 |
| 24 | 126360000 |
| 25 | 166359375 |
| 26 | 216751626 |
| 27 | 279695430 |
| 28 | 357694120 |
| 29 | 453635400 |
| 30 | 570834000 |
[1,30,270,1400,5250,15876,41160,95040,200475, 393250,726726,1277640,2153060,3498600,5508000, 8434176,12601845,18421830,26407150,37191000, 51546726,70409900,94902600,126360000,166359375, 216751626,279695430,357694120,453635400,570834000] |