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| n | a(n) |
|---|---|
| 1 | 81 |
| 2 | 452 |
| 3 | 1970 |
| 4 | 8128 |
| 5 | 33386 |
| 6 | 139390 |
| 7 | 588254 |
| 8 | 2496440 |
| 9 | 10620486 |
| 10 | 45235186 |
| 11 | 192770330 |
| 12 | 821702110 |
| 13 | 3502996038 |
| 14 | 14934443890 |
| 15 | 63672178746 |
| 16 | 271466142110 |
| 17 | 1157401680934 |
| 18 | 4934619974706 |
| 19 | 21038940313818 |
| 20 | 89700376749918 |
[81,452,1970,8128,33386,139390,588254,2496440, 10620486,45235186,192770330,821702110,3502996038, 14934443890,63672178746,271466142110, 1157401680934,4934619974706,21038940313818, 89700376749918] |