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| n | a(n) |
|---|---|
| 1 | 258 |
| 2 | 822 |
| 3 | 3016 |
| 4 | 10302 |
| 5 | 35486 |
| 6 | 122506 |
| 7 | 420420 |
| 8 | 1446744 |
| 9 | 4990438 |
| 10 | 17183040 |
| 11 | 59122262 |
| 12 | 203560110 |
| 13 | 701041422 |
| 14 | 2413836036 |
| 15 | 8310468310 |
| 16 | 28613117804 |
| 17 | 98520290558 |
| 18 | 339220390780 |
| 19 | 1167963347912 |
| 20 | 4021394031518 |
| 21 | 13846106821008 |
[258,822,3016,10302,35486,122506,420420,1446744, 4990438,17183040,59122262,203560110,701041422, 2413836036,8310468310,28613117804,98520290558, 339220390780,1167963347912,4021394031518, 13846106821008] |