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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 15 |
| 2 | 155 |
| 3 | 1332 |
| 4 | 8342 |
| 5 | 41586 |
| 6 | 174844 |
| 7 | 642815 |
| 8 | 2117690 |
| 9 | 6362806 |
| 10 | 17671203 |
| 11 | 45844681 |
| 12 | 112047610 |
| 13 | 259796057 |
| 14 | 574776968 |
| 15 | 1219349012 |
| 16 | 2490738686 |
| 17 | 4916477305 |
| 18 | 9406990883 |
| 19 | 17494038498 |
| 20 | 31695618318 |
| 21 | 56063910644 |
| 22 | 96993880940 |
| 23 | 164397619093 |
| 24 | 273384891666 |
| 25 | 446635565576 |
[1,15,155,1332,8342,41586,174844,642815,2117690, 6362806,17671203,45844681,112047610,259796057, 574776968,1219349012,2490738686,4916477305, 9406990883,17494038498,31695618318,56063910644, 96993880940,164397619093,273384891666, 446635565576] |