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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 6 |
| 3 | 22 |
| 4 | 88 |
| 5 | 362 |
| 6 | 1550 |
| 7 | 6778 |
| 8 | 30104 |
| 9 | 135458 |
| 10 | 616280 |
| 11 | 2825772 |
| 12 | 13050732 |
| 13 | 60641808 |
| 14 | 283188618 |
| 15 | 1328339472 |
| 16 | 6255474500 |
| 17 | 29558166908 |
| 18 | 140095615008 |
| 19 | 665841903428 |
| 20 | 3172346398542 |
| 21 | 15148207045422 |
| 22 | 72482131975406 |
| 23 | 347460312983430 |
| 24 | 1668482689041102 |
| 25 | 8024617166540062 |
| 26 | 38650704248517114 |
| 27 | 186413214485517048 |
[1,2,6,22,88,362,1550,6778,30104,135458,616280, 2825772,13050732,60641808,283188618,1328339472, 6255474500,29558166908,140095615008,665841903428, 3172346398542,15148207045422,72482131975406, 347460312983430,1668482689041102,8024617166540062, 38650704248517114,186413214485517048] |