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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 4 |
| 3 | 54 |
| 4 | 320 |
| 5 | 1250 |
| 6 | 3780 |
| 7 | 9604 |
| 8 | 21504 |
| 9 | 43740 |
| 10 | 82500 |
| 11 | 146410 |
| 12 | 247104 |
| 13 | 399854 |
| 14 | 624260 |
| 15 | 945000 |
| 16 | 1392640 |
| 17 | 2004504 |
| 18 | 2825604 |
| 19 | 3909630 |
| 20 | 5320000 |
| 21 | 7130970 |
| 22 | 9428804 |
| 23 | 12313004 |
| 24 | 15897600 |
| 25 | 20312500 |
| 26 | 25704900 |
| 27 | 32240754 |
| 28 | 40106304 |
| 29 | 49509670 |
| 30 | 60682500 |
| 31 | 73881680 |
| 32 | 89391104 |
[0,4,54,320,1250,3780,9604,21504,43740,82500, 146410,247104,399854,624260,945000,1392640, 2004504,2825604,3909630,5320000,7130970,9428804, 12313004,15897600,20312500,25704900,32240754, 40106304,49509670,60682500,73881680,89391104] |