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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 5 |
| 3 | 12 |
| 4 | 62 |
| 5 | 200 |
| 6 | 1065 |
| 7 | 3990 |
| 8 | 21714 |
| 9 | 89082 |
| 10 | 492366 |
| 11 | 2147376 |
| 12 | 12004740 |
| 13 | 54718092 |
| 14 | 308559537 |
| 15 | 1454116950 |
| 16 | 8255788970 |
| 17 | 39935276810 |
| 18 | 227976044010 |
| 19 | 1126178350440 |
| 20 | 6457854821340 |
| 21 | 32456552441040 |
| 22 | 186814834574550 |
| 23 | 952569927106980 |
| 24 | 5500292590186380 |
| 25 | 28391993275117500 |
[1,1,5,12,62,200,1065,3990,21714,89082,492366, 2147376,12004740,54718092,308559537,1454116950, 8255788970,39935276810,227976044010,1126178350440, 6457854821340,32456552441040,186814834574550, 952569927106980,5500292590186380, 28391993275117500] |