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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 7 |
| 3 | 26 |
| 4 | 105 |
| 5 | 438 |
| 6 | 1883 |
| 7 | 8261 |
| 8 | 36829 |
| 9 | 166217 |
| 10 | 757759 |
| 11 | 3482883 |
| 12 | 16118980 |
| 13 | 75034272 |
| 14 | 351040611 |
| 15 | 1649438104 |
| 16 | 7779730832 |
| 17 | 36817013598 |
| 18 | 174754037184 |
| 19 | 831695343920 |
| 20 | 3967751325946 |
| 21 | 18970059631721 |
| 22 | 90876481086451 |
| 23 | 436132617878930 |
| 24 | 2096548639639431 |
| 25 | 10093770798999128 |
| 26 | 48664640611491510 |
| 27 | 234930979186383682 |
[1,2,7,26,105,438,1883,8261,36829,166217,757759, 3482883,16118980,75034272,351040611,1649438104, 7779730832,36817013598,174754037184,831695343920, 3967751325946,18970059631721,90876481086451, 436132617878930,2096548639639431, 10093770798999128,48664640611491510, 234930979186383682] |