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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 3 |
| 3 | 7 |
| 4 | 28 |
| 5 | 77 |
| 6 | 328 |
| 7 | 1032 |
| 8 | 4561 |
| 9 | 15405 |
| 10 | 69769 |
| 11 | 247393 |
| 12 | 1138185 |
| 13 | 4185511 |
| 14 | 19468674 |
| 15 | 73609812 |
| 16 | 345276471 |
| 17 | 1334269657 |
| 18 | 6299899585 |
| 19 | 24782227361 |
| 20 | 117622225218 |
| 21 | 469582616810 |
| 22 | 2238340131739 |
| 23 | 9048089976912 |
| 24 | 43283737012166 |
| 25 | 176845107923360 |
| 26 | 848544854956430 |
| 27 | 3499129672077487 |
| 28 | 16833433325704218 |
[1,1,3,7,28,77,328,1032,4561,15405,69769,247393, 1138185,4185511,19468674,73609812,345276471, 1334269657,6299899585,24782227361,117622225218, 469582616810,2238340131739,9048089976912, 43283737012166,176845107923360,848544854956430, 3499129672077487,16833433325704218] |