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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 7 |
| 3 | 27 |
| 4 | 107 |
| 5 | 446 |
| 6 | 1881 |
| 7 | 8092 |
| 8 | 35281 |
| 9 | 155332 |
| 10 | 689317 |
| 11 | 3077837 |
| 12 | 13822709 |
| 13 | 62370888 |
| 14 | 282595987 |
| 15 | 1284860299 |
| 16 | 5859939781 |
| 17 | 26800809480 |
| 18 | 122881479385 |
| 19 | 564677253173 |
| 20 | 2600094786295 |
| 21 | 11994498454736 |
| 22 | 55425906674189 |
| 23 | 256520478250400 |
| 24 | 1188929043764117 |
| 25 | 5517825227850990 |
| 26 | 25640044127268883 |
| 27 | 119281290605788607 |
[1,2,7,27,107,446,1881,8092,35281,155332,689317, 3077837,13822709,62370888,282595987,1284860299, 5859939781,26800809480,122881479385,564677253173, 2600094786295,11994498454736,55425906674189, 256520478250400,1188929043764117,5517825227850990, 25640044127268883,119281290605788607] |