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| n | a(n) |
|---|---|
| 1 | 5 |
| 2 | 25 |
| 3 | 120 |
| 4 | 570 |
| 5 | 2670 |
| 6 | 12390 |
| 7 | 57030 |
| 8 | 260790 |
| 9 | 1185990 |
| 10 | 5368470 |
| 11 | 24204390 |
| 12 | 108756150 |
| 13 | 487223430 |
| 14 | 2177121750 |
| 15 | 9706364070 |
| 16 | 43188455670 |
| 17 | 191830083270 |
| 18 | 850727111190 |
| 19 | 3767586342630 |
| 20 | 16664819732790 |
| 21 | 73630769405190 |
| 22 | 325004395216470 |
[5,25,120,570,2670,12390,57030,260790,1185990, 5368470,24204390,108756150,487223430,2177121750, 9706364070,43188455670,191830083270,850727111190, 3767586342630,16664819732790,73630769405190, 325004395216470] |