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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 10 |
| 3 | 58 |
| 4 | 370 |
| 5 | 2514 |
| 6 | 17850 |
| 7 | 130890 |
| 8 | 983650 |
| 9 | 7536418 |
| 10 | 58648810 |
| 11 | 462306266 |
| 12 | 3683602130 |
| 13 | 29620138994 |
| 14 | 240059315610 |
| 15 | 1958940281322 |
| 16 | 16081662931650 |
| 17 | 132723191430210 |
| 18 | 1100568370427850 |
| 19 | 9164925012016506 |
| 20 | 76612776253995570 |
[1,2,10,58,370,2514,17850,130890,983650,7536418, 58648810,462306266,3683602130,29620138994, 240059315610,1958940281322,16081662931650, 132723191430210,1100568370427850,9164925012016506, 76612776253995570] |