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| n | a(n) |
|---|---|
| 1 | 13 |
| 2 | 43 |
| 3 | 162 |
| 4 | 672 |
| 5 | 2962 |
| 6 | 13540 |
| 7 | 63221 |
| 8 | 298775 |
| 9 | 1421589 |
| 10 | 6789700 |
| 11 | 32497044 |
| 12 | 155720725 |
| 13 | 746674943 |
| 14 | 3581570065 |
| 15 | 17183126915 |
| 16 | 82447803666 |
| 17 | 395624032453 |
| 18 | 1898458134570 |
| 19 | 9110192964029 |
| 20 | 43717837035318 |
| 21 | 209793618176126 |
[13,43,162,672,2962,13540,63221,298775,1421589, 6789700,32497044,155720725,746674943,3581570065, 17183126915,82447803666,395624032453, 1898458134570,9110192964029,43717837035318, 209793618176126] |