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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 4 |
| 3 | 9 |
| 4 | 39 |
| 5 | 112 |
| 6 | 511 |
| 7 | 1655 |
| 8 | 7754 |
| 9 | 27061 |
| 10 | 128714 |
| 11 | 472720 |
| 12 | 2270366 |
| 13 | 8651976 |
| 14 | 41837362 |
| 15 | 163948096 |
| 16 | 796796614 |
| 17 | 3191331555 |
| 18 | 15570137360 |
| 19 | 63466080257 |
| 20 | 310584371757 |
| 21 | 1284389855918 |
| 22 | 6300697460577 |
| 23 | 26372512380003 |
| 24 | 129628574987488 |
| 25 | 548174480986494 |
| 26 | 2698834335089730 |
| 27 | 11513980004561963 |
| 28 | 56764309192152032 |
[1,1,4,9,39,112,511,1655,7754,27061,128714,472720, 2270366,8651976,41837362,163948096,796796614, 3191331555,15570137360,63466080257,310584371757, 1284389855918,6300697460577,26372512380003, 129628574987488,548174480986494,2698834335089730, 11513980004561963,56764309192152032] |