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| n | a(n) |
|---|---|
| 1 | 2 |
| 2 | 15 |
| 3 | 26 |
| 4 | 58 |
| 5 | 152 |
| 6 | 325 |
| 7 | 729 |
| 8 | 1609 |
| 9 | 3577 |
| 10 | 7931 |
| 11 | 17605 |
| 12 | 39106 |
| 13 | 86859 |
| 14 | 192976 |
| 15 | 428779 |
| 16 | 952794 |
| 17 | 2117289 |
| 18 | 4705103 |
| 19 | 10455942 |
| 20 | 23235911 |
| 21 | 51636607 |
| 22 | 114750985 |
| 23 | 255009010 |
| 24 | 566702101 |
| 25 | 1259372546 |
| 26 | 2798682776 |
| 27 | 6219466851 |
| 28 | 13821419716 |
| 29 | 30715116147 |
[2,15,26,58,152,325,729,1609,3577,7931,17605, 39106,86859,192976,428779,952794,2117289,4705103, 10455942,23235911,51636607,114750985,255009010, 566702101,1259372546,2798682776,6219466851, 13821419716,30715116147] |