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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 6 |
| 4 | 21 |
| 5 | 79 |
| 6 | 309 |
| 7 | 1237 |
| 8 | 5026 |
| 9 | 20626 |
| 10 | 85242 |
| 11 | 354080 |
| 12 | 1476368 |
| 13 | 6173634 |
| 14 | 25873744 |
| 15 | 108628550 |
| 16 | 456710589 |
| 17 | 1922354351 |
| 18 | 8098984433 |
| 19 | 34147706833 |
| 20 | 144068881455 |
| 21 | 608151037123 |
| 22 | 2568318694867 |
| 23 | 10850577045131 |
| 24 | 45856273670841 |
| 25 | 193850277807569 |
| 26 | 819669810565949 |
[1,1,2,6,21,79,309,1237,5026,20626,85242,354080, 1476368,6173634,25873744,108628550,456710589, 1922354351,8098984433,34147706833,144068881455, 608151037123,2568318694867,10850577045131, 45856273670841,193850277807569,819669810565949] |