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| n | a(n) |
|---|---|
| 1 | 15 |
| 2 | 30 |
| 3 | 91 |
| 4 | 229 |
| 5 | 612 |
| 6 | 1593 |
| 7 | 4183 |
| 8 | 10942 |
| 9 | 28659 |
| 10 | 75021 |
| 11 | 196420 |
| 12 | 514225 |
| 13 | 1346271 |
| 14 | 3524574 |
| 15 | 9227467 |
| 16 | 24157813 |
| 17 | 63245988 |
| 18 | 165580137 |
| 19 | 433494439 |
| 20 | 1134903166 |
| 21 | 2971215075 |
| 22 | 7778742045 |
| 23 | 20365011076 |
| 24 | 53316291169 |
| 25 | 139583862447 |
| 26 | 365435296158 |
| 27 | 956722026043 |
| 28 | 2504730781957 |
[15,30,91,229,612,1593,4183,10942,28659,75021, 196420,514225,1346271,3524574,9227467,24157813, 63245988,165580137,433494439,1134903166, 2971215075,7778742045,20365011076,53316291169, 139583862447,365435296158,956722026043, 2504730781957] |