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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 7 |
| 3 | 26 |
| 4 | 106 |
| 5 | 433 |
| 6 | 1840 |
| 7 | 7940 |
| 8 | 34600 |
| 9 | 152415 |
| 10 | 677408 |
| 11 | 3026920 |
| 12 | 13601908 |
| 13 | 61423330 |
| 14 | 278412139 |
| 15 | 1266274777 |
| 16 | 5777664180 |
| 17 | 26431866609 |
| 18 | 121211063067 |
| 19 | 557094467005 |
| 20 | 2565518805088 |
| 21 | 11835880142484 |
| 22 | 54695962523709 |
| 23 | 253149015388344 |
| 24 | 1173298821523358 |
| 25 | 5445202284648577 |
| 26 | 25301849449310989 |
| 27 | 117702463118949106 |
[1,2,7,26,106,433,1840,7940,34600,152415,677408, 3026920,13601908,61423330,278412139,1266274777, 5777664180,26431866609,121211063067,557094467005, 2565518805088,11835880142484,54695962523709, 253149015388344,1173298821523358,5445202284648577, 25301849449310989,117702463118949106] |