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 | 29 |
| 3 | 297 |
| 4 | 2801 |
| 5 | 24993 |
| 6 | 215489 |
| 7 | 1817217 |
| 8 | 15097601 |
| 9 | 124140033 |
| 10 | 1013275649 |
| 11 | 8227137537 |
| 12 | 66542694401 |
| 13 | 536695119873 |
| 14 | 4319682347009 |
| 15 | 34714187104257 |
| 16 | 278653866803201 |
| 17 | 2234873154240513 |
| 18 | 17912838552813569 |
| 19 | 143505828335845377 |