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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 1 |
| 2 | 5 |
| 3 | 20 |
| 4 | 75 |
| 5 | 275 |
| 6 | 1000 |
| 7 | 3625 |
| 8 | 13125 |
| 9 | 47500 |
| 10 | 171875 |
| 11 | 621875 |
| 12 | 2250000 |
| 13 | 8140625 |
| 14 | 29453125 |
| 15 | 106562500 |
| 16 | 385546875 |
| 17 | 1394921875 |
| 18 | 5046875000 |
| 19 | 18259765625 |
| 20 | 66064453125 |
| 21 | 239023437500 |
| 22 | 864794921875 |
| 23 | 3128857421875 |
| 24 | 11320312500000 |
| 25 | 40957275390625 |
| 26 | 148184814453125 |
[0,1,5,20,75,275,1000,3625,13125,47500,171875, 621875,2250000,8140625,29453125,106562500, 385546875,1394921875,5046875000,18259765625, 66064453125,239023437500,864794921875, 3128857421875,11320312500000,40957275390625, 148184814453125] |