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 | 0 |
| 2 | 21 |
| 3 | 543 |
| 4 | 9876 |
| 5 | 1413121110 |
| 6 | 201918171615 |
| 7 | 27262524232221 |
| 8 | 3534333231302928 |
| 9 | 444342414039383736 |
| 10 | 54535251504948474645 |
| 11 | 6564636261605958575655 |
| 12 | 777675747372717069686766 |
| 13 | 90898887868584838281807978 |