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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 7 |
| 3 | 24 |
| 4 | 97 |
| 5 | 391 |
| 6 | 1672 |
| 7 | 7232 |
| 8 | 32095 |
| 9 | 143890 |
| 10 | 654576 |
| 11 | 3001579 |
| 12 | 13885346 |
| 13 | 64649472 |
| 14 | 302799239 |
| 15 | 1425079734 |
| 16 | 6737118346 |
| 17 | 31968585995 |
| 18 | 152210064193 |
| 19 | 726892427717 |
| 20 | 3480598873598 |
| 21 | 16706218528946 |
| 22 | 80362739968924 |
| 23 | 387329882769961 |
| 24 | 1870188929001891 |
| 25 | 9044941975505991 |
| 26 | 43810266592179082 |
| 27 | 212493330136638586 |
[1,2,7,24,97,391,1672,7232,32095,143890,654576, 3001579,13885346,64649472,302799239,1425079734, 6737118346,31968585995,152210064193,726892427717, 3480598873598,16706218528946,80362739968924, 387329882769961,1870188929001891,9044941975505991, 43810266592179082,212493330136638586] |