This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
| n | a(n) |
|---|---|
| 1 | 9 |
| 2 | 81 |
| 3 | 387 |
| 4 | 2205 |
| 5 | 12015 |
| 6 | 66339 |
| 7 | 364869 |
| 8 | 2009223 |
| 9 | 11059965 |
| 10 | 60888177 |
| 11 | 335192787 |
| 12 | 1845279405 |
| 13 | 10158455727 |
| 14 | 55923440859 |
| 15 | 307864679445 |
| 16 | 1694829122631 |
| 17 | 9330221332989 |
| 18 | 51363898889337 |
| 19 | 282763934436339 |
| 20 | 1556646681947805 |