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| n | a(n) |
|---|---|
| 0 | 2 |
| 1 | 8 |
| 2 | 46 |
| 3 | 268 |
| 4 | 1562 |
| 5 | 9104 |
| 6 | 53062 |
| 7 | 309268 |
| 8 | 1802546 |
| 9 | 10506008 |
| 10 | 61233502 |
| 11 | 356895004 |
| 12 | 2080136522 |
| 13 | 12123924128 |
| 14 | 70663408246 |
| 15 | 411856525348 |
| 16 | 2400475743842 |
| 17 | 13990997937704 |
| 18 | 81545511882382 |
| 19 | 475282073356588 |
| 20 | 2770146928257146 |
| 21 | 16145599496186288 |
| 22 | 94103450048860582 |
[2,8,46,268,1562,9104,53062,309268,1802546, 10506008,61233502,356895004,2080136522, 12123924128,70663408246,411856525348, 2400475743842,13990997937704,81545511882382, 475282073356588,2770146928257146, 16145599496186288,94103450048860582] |