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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 3 |
| 3 | 8 |
| 4 | 26 |
| 5 | 88 |
| 6 | 315 |
| 7 | 1171 |
| 8 | 4477 |
| 9 | 17546 |
| 10 | 70066 |
| 11 | 284471 |
| 12 | 1170797 |
| 13 | 4876190 |
| 14 | 20517751 |
| 15 | 87111609 |
| 16 | 372793818 |
| 17 | 1606639972 |
| 18 | 6968002247 |
| 19 | 30392051069 |
| 20 | 133241561658 |
| 21 | 586871095960 |
| 22 | 2595923416225 |
| 23 | 11527409347635 |
| 24 | 51371869596583 |
| 25 | 229695131462288 |
| 26 | 1030156580857929 |
| 27 | 4633227156569544 |
| 28 | 20893278979205582 |
[1,1,3,8,26,88,315,1171,4477,17546,70066,284471, 1170797,4876190,20517751,87111609,372793818, 1606639972,6968002247,30392051069,133241561658, 586871095960,2595923416225,11527409347635, 51371869596583,229695131462288,1030156580857929, 4633227156569544,20893278979205582] |