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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 8 |
| 3 | 26 |
| 4 | 120 |
| 5 | 445 |
| 6 | 2106 |
| 7 | 8302 |
| 8 | 40075 |
| 9 | 163934 |
| 10 | 797561 |
| 11 | 3341834 |
| 12 | 16370003 |
| 13 | 69800886 |
| 14 | 343163275 |
| 15 | 1482329691 |
| 16 | 7311311272 |
| 17 | 31907997150 |
| 18 | 157698550081 |
| 19 | 693887774764 |
| 20 | 3435657381930 |
| 21 | 15220483718537 |
| 22 | 75456187238874 |
| 23 | 336186700906527 |
| 24 | 1668558215343475 |
| 25 | 7470397836029163 |
| 26 | 37108210390926633 |
| 27 | 166837300163396705 |
[1,2,8,26,120,445,2106,8302,40075,163934,797561, 3341834,16370003,69800886,343163275,1482329691, 7311311272,31907997150,157698550081,693887774764, 3435657381930,15220483718537,75456187238874, 336186700906527,1668558215343475,7470397836029163, 37108210390926633,166837300163396705] |