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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 2 |
| 3 | 2 |
| 4 | 14 |
| 5 | 78 |
| 6 | 406 |
| 7 | 2062 |
| 8 | 10374 |
| 9 | 51998 |
| 10 | 260246 |
| 11 | 1301742 |
| 12 | 6509734 |
| 13 | 32550718 |
| 14 | 162757686 |
| 15 | 813796622 |
| 16 | 4068999494 |
| 17 | 20345030238 |
| 18 | 101725216726 |
| 19 | 508626214702 |
| 20 | 2543131335654 |
| 21 | 12715657202558 |
| 22 | 63578287061366 |
| 23 | 317891437403982 |
[1,2,2,14,78,406,2062,10374,51998,260246,1301742, 6509734,32550718,162757686,813796622,4068999494, 20345030238,101725216726,508626214702, 2543131335654,12715657202558,63578287061366, 317891437403982] |