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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 10 |
| 3 | 36 |
| 4 | 166 |
| 5 | 556 |
| 6 | 2724 |
| 7 | 9000 |
| 8 | 41542 |
| 9 | 153164 |
| 10 | 657644 |
| 11 | 2325816 |
| 12 | 11020508 |
| 13 | 38006264 |
| 14 | 164662664 |
| 15 | 634362320 |
| 16 | 2695771462 |
| 17 | 9775537676 |
| 18 | 43527018396 |
| 19 | 156855914904 |
| 20 | 687387270260 |
| 21 | 2605392165928 |
| 22 | 10799896586616 |
| 23 | 40214700074800 |
| 24 | 178809945153820 |
| 25 | 657023566793400 |
[1,2,10,36,166,556,2724,9000,41542,153164,657644, 2325816,11020508,38006264,164662664,634362320, 2695771462,9775537676,43527018396,156855914904, 687387270260,2605392165928,10799896586616, 40214700074800,178809945153820,657023566793400] |