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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 3 |
| 3 | 6 |
| 4 | 25 |
| 5 | 65 |
| 6 | 263 |
| 7 | 818 |
| 8 | 3460 |
| 9 | 11295 |
| 10 | 49589 |
| 11 | 171337 |
| 12 | 756364 |
| 13 | 2728977 |
| 14 | 12218413 |
| 15 | 45154693 |
| 16 | 204526668 |
| 17 | 774395008 |
| 18 | 3523749667 |
| 19 | 13608411568 |
| 20 | 62334220137 |
| 21 | 244098295369 |
| 22 | 1124429301897 |
| 23 | 4462694940662 |
| 24 | 20623721325354 |
| 25 | 82801756928869 |
| 26 | 384104350127336 |
| 27 | 1556170558698583 |
| 28 | 7243115019135401 |
[1,1,3,6,25,65,263,818,3460,11295,49589,171337, 756364,2728977,12218413,45154693,204526668, 774395008,3523749667,13608411568,62334220137, 244098295369,1124429301897,4462694940662, 20623721325354,82801756928869,384104350127336, 1556170558698583,7243115019135401] |