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| n | a(n) |
|---|---|
| 1 | 50 |
| 2 | 254 |
| 3 | 946 |
| 4 | 4254 |
| 5 | 17794 |
| 6 | 79782 |
| 7 | 350266 |
| 8 | 1574348 |
| 9 | 7039308 |
| 10 | 31791832 |
| 11 | 143422488 |
| 12 | 649853710 |
| 13 | 2944761666 |
| 14 | 13369773598 |
| 15 | 60719993934 |
| 16 | 276010194872 |
| 17 | 1254976548136 |
| 18 | 5708622661652 |
| 19 | 25972110429080 |
| 20 | 118188673239130 |
| 21 | 537890728864526 |
[50,254,946,4254,17794,79782,350266,1574348, 7039308,31791832,143422488,649853710,2944761666, 13369773598,60719993934,276010194872, 1254976548136,5708622661652,25972110429080, 118188673239130,537890728864526] |