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 | 3 |
| 2 | 81 |
| 3 | 1215 |
| 4 | 15309 |
| 5 | 177147 |
| 6 | 1948617 |
| 7 | 20726199 |
| 8 | 215233605 |
| 9 | 2195382771 |
| 10 | 22082967873 |
| 11 | 219667417263 |
| 12 | 2165293113021 |
| 13 | 21182215236075 |
| 14 | 205891132094649 |
| 15 | 1990280943581607 |
| 16 | 19147875284802357 |
| 17 | 183448998696332259 |
| 18 | 1751104078464989745 |
| 19 | 16660504517966902431 |