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| n | a(n) |
|---|---|
| 1 | 21 |
| 2 | 35 |
| 3 | 132 |
| 4 | 443 |
| 5 | 1803 |
| 6 | 7795 |
| 7 | 33860 |
| 8 | 148299 |
| 9 | 646838 |
| 10 | 2827081 |
| 11 | 12348295 |
| 12 | 53946658 |
| 13 | 235669276 |
| 14 | 1029543928 |
| 15 | 4497666250 |
| 16 | 19648472006 |
| 17 | 85836276153 |
| 18 | 374983965881 |
| 19 | 1638153628134 |
| 20 | 7156431645355 |
| 21 | 31263560215566 |
| 22 | 136577871103739 |
[21,35,132,443,1803,7795,33860,148299,646838, 2827081,12348295,53946658,235669276,1029543928, 4497666250,19648472006,85836276153,374983965881, 1638153628134,7156431645355,31263560215566, 136577871103739] |