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| n | a(n) |
|---|---|
| 1 | 5 |
| 2 | 25 |
| 3 | 120 |
| 4 | 567 |
| 5 | 2637 |
| 6 | 12125 |
| 7 | 55225 |
| 8 | 249600 |
| 9 | 1120868 |
| 10 | 5006144 |
| 11 | 22255415 |
| 12 | 98544130 |
| 13 | 434827380 |
| 14 | 1912861067 |
| 15 | 8392454605 |
| 16 | 36733957588 |
| 17 | 160447861687 |
| 18 | 699496998228 |
| 19 | 3044446874255 |
| 20 | 13230474539089 |
| 21 | 57418454111103 |
| 22 | 248881927670961 |
[5,25,120,567,2637,12125,55225,249600,1120868, 5006144,22255415,98544130,434827380,1912861067, 8392454605,36733957588,160447861687,699496998228, 3044446874255,13230474539089,57418454111103, 248881927670961] |