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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 9 |
| 3 | 64 |
| 4 | 549 |
| 5 | 4566 |
| 6 | 34711 |
| 7 | 243944 |
| 8 | 1622025 |
| 9 | 10402858 |
| 10 | 65219931 |
| 11 | 403119036 |
| 12 | 2469129229 |
| 13 | 15032191422 |
| 14 | 91123985023 |
| 15 | 550590488656 |
| 16 | 3318118088721 |
| 17 | 19953003487314 |
| 18 | 119759533521571 |
| 19 | 717624299625188 |
| 20 | 4293868352394261 |
| 21 | 25658433286034662 |
| 22 | 153142720988745159 |
| 23 | 913049836619756664 |
[1,2,9,64,549,4566,34711,243944,1622025,10402858, 65219931,403119036,2469129229,15032191422, 91123985023,550590488656,3318118088721, 19953003487314,119759533521571,717624299625188, 4293868352394261,25658433286034662, 153142720988745159,913049836619756664] |