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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 4 |
| 3 | 10 |
| 4 | 33 |
| 5 | 105 |
| 6 | 363 |
| 7 | 1268 |
| 8 | 4600 |
| 9 | 16954 |
| 10 | 63663 |
| 11 | 242180 |
| 12 | 932255 |
| 13 | 3623239 |
| 14 | 14200924 |
| 15 | 56061965 |
| 16 | 222728379 |
| 17 | 889828825 |
| 18 | 3572675122 |
| 19 | 14408128581 |
| 20 | 58338540673 |
| 21 | 237067134533 |
| 22 | 966522205819 |
| 23 | 3952323714926 |
| 24 | 16206324436147 |
| 25 | 66621153183615 |
| 26 | 274505283101713 |
[1,1,4,10,33,105,363,1268,4600,16954,63663,242180, 932255,3623239,14200924,56061965,222728379, 889828825,3572675122,14408128581,58338540673, 237067134533,966522205819,3952323714926, 16206324436147,66621153183615,274505283101713] |