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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 5 |
| 2 | 15 |
| 3 | 46 |
| 4 | 159 |
| 5 | 570 |
| 6 | 2036 |
| 7 | 7208 |
| 8 | 25400 |
| 9 | 89456 |
| 10 | 315335 |
| 11 | 1112286 |
| 12 | 3923867 |
| 13 | 13841052 |
| 14 | 48818892 |
| 15 | 172186234 |
| 16 | 607314043 |
| 17 | 2142064478 |
| 18 | 7555322206 |
| 19 | 26648517536 |
| 20 | 93992371863 |
| 21 | 331521717928 |
| 22 | 1169314641890 |
| 23 | 4124305724658 |
| 24 | 14546896171716 |
| 25 | 51308559972146 |
| 26 | 180971133233105 |
| 27 | 638305788168090 |
[1,5,15,46,159,570,2036,7208,25400,89456,315335, 1112286,3923867,13841052,48818892,172186234, 607314043,2142064478,7555322206,26648517536, 93992371863,331521717928,1169314641890, 4124305724658,14546896171716,51308559972146, 180971133233105,638305788168090] |