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| n | a(n) |
|---|---|
| 0 | 3 |
| 1 | 6 |
| 2 | 14 |
| 3 | 31 |
| 4 | 70 |
| 5 | 156 |
| 6 | 349 |
| 7 | 780 |
| 8 | 1745 |
| 9 | 3901 |
| 10 | 8723 |
| 11 | 19505 |
| 12 | 43615 |
| 13 | 97526 |
| 14 | 218075 |
| 15 | 487630 |
| 16 | 1090374 |
| 17 | 2438150 |
| 18 | 5451870 |
| 19 | 12190751 |
| 20 | 27259348 |
| 21 | 60953755 |
| 22 | 136296740 |
| 23 | 304768775 |
| 24 | 681483699 |
| 25 | 1523843876 |
| 26 | 3407418494 |
| 27 | 7619219380 |
| 28 | 17037092470 |
[3,6,14,31,70,156,349,780,1745,3901,8723,19505, 43615,97526,218075,487630,1090374,2438150,5451870, 12190751,27259348,60953755,136296740,304768775, 681483699,1523843876,3407418494,7619219380, 17037092470] |