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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 7 |
| 4 | 27 |
| 5 | 112 |
| 6 | 492 |
| 7 | 2243 |
| 8 | 10513 |
| 9 | 50353 |
| 10 | 245353 |
| 11 | 1212398 |
| 12 | 6061225 |
| 13 | 30601910 |
| 14 | 155808915 |
| 15 | 799096655 |
| 16 | 4124491215 |
| 17 | 21408066097 |
| 18 | 111672838857 |
| 19 | 585128521777 |
| 20 | 3078178384457 |
| 21 | 16252057372887 |
| 22 | 86089680204939 |
| 23 | 457400940705274 |
| 24 | 2436895852070559 |
| 25 | 13015917111573039 |
[1,1,2,7,27,112,492,2243,10513,50353,245353, 1212398,6061225,30601910,155808915,799096655, 4124491215,21408066097,111672838857,585128521777, 3078178384457,16252057372887,86089680204939, 457400940705274,2436895852070559, 13015917111573039] |