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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 7 |
| 4 | 24 |
| 5 | 86 |
| 6 | 316 |
| 7 | 1177 |
| 8 | 4424 |
| 9 | 16744 |
| 10 | 63724 |
| 11 | 243618 |
| 12 | 934870 |
| 13 | 3598960 |
| 14 | 13892776 |
| 15 | 53756263 |
| 16 | 208434024 |
| 17 | 809658440 |
| 18 | 3150218032 |
| 19 | 12274694280 |
| 20 | 47890456576 |
| 21 | 187068828772 |
| 22 | 731511810152 |
| 23 | 2863308366462 |
| 24 | 11217762520246 |
| 25 | 43984983838966 |
[1,1,2,7,24,86,316,1177,4424,16744,63724,243618, 934870,3598960,13892776,53756263,208434024, 809658440,3150218032,12274694280,47890456576, 187068828772,731511810152,2863308366462, 11217762520246,43984983838966] |