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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 5 |
| 3 | 18 |
| 4 | 67 |
| 5 | 255 |
| 6 | 1051 |
| 7 | 4369 |
| 8 | 18572 |
| 9 | 80952 |
| 10 | 354452 |
| 11 | 1578206 |
| 12 | 7087756 |
| 13 | 32022176 |
| 14 | 146097555 |
| 15 | 669267386 |
| 16 | 3084216216 |
| 17 | 14286647804 |
| 18 | 66396900479 |
| 19 | 309990281251 |
| 20 | 1451626208083 |
| 21 | 6818529025761 |
| 22 | 32126482382026 |
| 23 | 151710234242601 |
| 24 | 718259705285107 |
| 25 | 3407732027062404 |
| 26 | 16199219318914725 |
| 27 | 77157761484968208 |
[1,2,5,18,67,255,1051,4369,18572,80952,354452, 1578206,7087756,32022176,146097555,669267386, 3084216216,14286647804,66396900479,309990281251, 1451626208083,6818529025761,32126482382026, 151710234242601,718259705285107,3407732027062404, 16199219318914725,77157761484968208] |