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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 3 |
| 3 | 8 |
| 4 | 28 |
| 5 | 91 |
| 6 | 339 |
| 7 | 1191 |
| 8 | 4673 |
| 9 | 17489 |
| 10 | 70829 |
| 11 | 275583 |
| 12 | 1140249 |
| 13 | 4555059 |
| 14 | 19176287 |
| 15 | 78180708 |
| 16 | 333655636 |
| 17 | 1382789189 |
| 18 | 5964790733 |
| 19 | 25047746365 |
| 20 | 108998800785 |
| 21 | 462656900979 |
| 22 | 2028379249377 |
| 23 | 8687945066980 |
| 24 | 38332181892050 |
| 25 | 165464671038519 |
| 26 | 734031617783073 |
| 27 | 3189844310837718 |
| 28 | 14217991701913836 |
[1,1,3,8,28,91,339,1191,4673,17489,70829,275583, 1140249,4555059,19176287,78180708,333655636, 1382789189,5964790733,25047746365,108998800785, 462656900979,2028379249377,8687945066980, 38332181892050,165464671038519,734031617783073, 3189844310837718,14217991701913836] |