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| n | a(n) |
|---|---|
| 1 | 60 |
| 2 | 290 |
| 3 | 1202 |
| 4 | 5848 |
| 5 | 28452 |
| 6 | 135912 |
| 7 | 640926 |
| 8 | 2990786 |
| 9 | 13835892 |
| 10 | 63544542 |
| 11 | 290056316 |
| 12 | 1317009868 |
| 13 | 5952527788 |
| 14 | 26795651036 |
| 15 | 120193389832 |
| 16 | 537427198324 |
| 17 | 2396207992178 |
| 18 | 10656560102448 |
| 19 | 47282655935580 |
| 20 | 209348341875062 |
[60,290,1202,5848,28452,135912,640926,2990786, 13835892,63544542,290056316,1317009868,5952527788, 26795651036,120193389832,537427198324, 2396207992178,10656560102448,47282655935580, 209348341875062] |