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) |
|---|---|
| 0 | 1 |
| 1 | 3 |
| 2 | 21 |
| 3 | 162 |
| 4 | 1341 |
| 5 | 11529 |
| 6 | 101619 |
| 7 | 911466 |
| 8 | 8281737 |
| 9 | 76002381 |
| 10 | 703017549 |
| 11 | 6544803564 |
| 12 | 61254970686 |
| 13 | 575885086182 |
| 14 | 5434948357146 |
| 15 | 51462813578148 |
| 16 | 488705091057981 |
| 17 | 4652700300002475 |
| 18 | 44395945025504625 |
| 19 | 424479488258350350 |