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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 1 |
| 3 | 3 |
| 4 | 9 |
| 5 | 33 |
| 6 | 153 |
| 7 | 731 |
| 8 | 4273 |
| 9 | 25857 |
| 10 | 177489 |
| 11 | 1311379 |
| 12 | 10342137 |
| 13 | 89060065 |
| 14 | 800697641 |
| 15 | 7778778091 |
| 16 | 78896218081 |
| 17 | 849264442881 |
| 18 | 9587206592289 |
| 19 | 113234181108643 |
| 20 | 1403875965476969 |
| 21 | 18073465545032353 |
| 22 | 243412313149166137 |
| 23 | 3395124358886313595 |
| 24 | 49273184499900888465 |
[1,1,1,3,9,33,153,731,4273,25857,177489,1311379, 10342137,89060065,800697641,7778778091, 78896218081,849264442881,9587206592289, 113234181108643,1403875965476969, 18073465545032353,243412313149166137, 3395124358886313595,49273184499900888465] |