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| n | a(n) |
|---|---|
| 1 | 2 |
| 2 | 3 |
| 3 | 10 |
| 4 | 40 |
| 5 | 170 |
| 6 | 785 |
| 7 | 3770 |
| 8 | 18805 |
| 9 | 96180 |
| 10 | 502381 |
| 11 | 2667034 |
| 12 | 14351775 |
| 13 | 78096654 |
| 14 | 429025553 |
| 15 | 2376075922 |
| 16 | 13252492311 |
| 17 | 74372374366 |
| 18 | 419651663108 |
| 19 | 2379399524742 |
| 20 | 13549601275893 |
| 21 | 77460249369658 |
| 22 | 444389519874841 |
[2,3,10,40,170,785,3770,18805,96180,502381, 2667034,14351775,78096654,429025553,2376075922, 13252492311,74372374366,419651663108, 2379399524742,13549601275893,77460249369658, 444389519874841] |