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| n | a(n) |
|---|---|
| 1 | 16 |
| 2 | 57 |
| 3 | 454 |
| 4 | 1792 |
| 5 | 10788 |
| 6 | 43999 |
| 7 | 226126 |
| 8 | 874205 |
| 9 | 4025000 |
| 10 | 15472252 |
| 11 | 66378320 |
| 12 | 251166657 |
| 13 | 1040520624 |
| 14 | 3937703717 |
| 15 | 16021122364 |
| 16 | 60678306334 |
| 17 | 245065674186 |
| 18 | 932218789579 |
| 19 | 3750451651646 |
| 20 | 14310037237132 |
| 21 | 57374909585066 |
[16,57,454,1792,10788,43999,226126,874205,4025000, 15472252,66378320,251166657,1040520624,3937703717, 16021122364,60678306334,245065674186,932218789579, 3750451651646,14310037237132,57374909585066] |