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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 7 |
| 3 | 25 |
| 4 | 102 |
| 5 | 421 |
| 6 | 1825 |
| 7 | 8006 |
| 8 | 35895 |
| 9 | 162577 |
| 10 | 744984 |
| 11 | 3439518 |
| 12 | 15996637 |
| 13 | 74810939 |
| 14 | 351643452 |
| 15 | 1659782629 |
| 16 | 7863638164 |
| 17 | 37376167597 |
| 18 | 178163667538 |
| 19 | 851434786181 |
| 20 | 4078328364701 |
| 21 | 19575398037485 |
| 22 | 94135706779259 |
| 23 | 453460880431690 |
| 24 | 2187782728505327 |
| 25 | 10570405822198023 |
| 26 | 51139156672554917 |
| 27 | 247711683227059228 |
[1,2,7,25,102,421,1825,8006,35895,162577,744984, 3439518,15996637,74810939,351643452,1659782629, 7863638164,37376167597,178163667538,851434786181, 4078328364701,19575398037485,94135706779259, 453460880431690,2187782728505327, 10570405822198023,51139156672554917, 247711683227059228] |