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| n | a(n) |
|---|---|
| 0 | 2 |
| 1 | 15 |
| 2 | 69 |
| 3 | 252 |
| 4 | 804 |
| 5 | 2349 |
| 6 | 6455 |
| 7 | 16962 |
| 8 | 43086 |
| 9 | 106587 |
| 10 | 258153 |
| 11 | 614520 |
| 12 | 1441928 |
| 13 | 3342489 |
| 14 | 7667883 |
| 15 | 17432766 |
| 16 | 39321810 |
| 17 | 88080615 |
| 18 | 196083965 |
| 19 | 434110740 |
| 20 | 956301612 |
| 21 | 2097152325 |
| 22 | 4580180319 |
| 23 | 9965666682 |
| 24 | 21609054614 |
| 25 | 46707769779 |
[2,15,69,252,804,2349,6455,16962,43086,106587, 258153,614520,1441928,3342489,7667883,17432766, 39321810,88080615,196083965,434110740,956301612, 2097152325,4580180319,9965666682,21609054614, 46707769779] |