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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 3 |
| 2 | 6 |
| 3 | 14 |
| 4 | 30 |
| 5 | 66 |
| 6 | 142 |
| 7 | 306 |
| 8 | 654 |
| 9 | 1394 |
| 10 | 2958 |
| 11 | 6258 |
| 12 | 13198 |
| 13 | 27762 |
| 14 | 58254 |
| 15 | 121970 |
| 16 | 254862 |
| 17 | 531570 |
| 18 | 1106830 |
| 19 | 2301042 |
| 20 | 4776846 |
| 21 | 9903218 |
| 22 | 20505486 |
| 23 | 42409074 |
| 24 | 87614350 |
| 25 | 180821106 |
| 26 | 372827022 |
| 27 | 768023666 |
| 28 | 1580786574 |
| 29 | 3251051634 |
[1,3,6,14,30,66,142,306,654,1394,2958,6258,13198, 27762,58254,121970,254862,531570,1106830,2301042, 4776846,9903218,20505486,42409074,87614350, 180821106,372827022,768023666,1580786574, 3251051634] |