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| n | a(n) |
|---|---|
| 1 | 20 |
| 2 | 114 |
| 3 | 1448 |
| 4 | 15360 |
| 5 | 149336 |
| 6 | 1346477 |
| 7 | 11432523 |
| 8 | 90627413 |
| 9 | 672437960 |
| 10 | 4724581523 |
| 11 | 31737220657 |
| 12 | 204660108794 |
| 13 | 1268432419949 |
| 14 | 7564543799888 |
| 15 | 43494599738604 |
| 16 | 241678326267770 |
| 17 | 1300626138728509 |
| 18 | 6792490340804235 |
| 19 | 34484471821861910 |
[20,114,1448,15360,149336,1346477,11432523, 90627413,672437960,4724581523,31737220657, 204660108794,1268432419949,7564543799888, 43494599738604,241678326267770,1300626138728509, 6792490340804235,34484471821861910] |