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 | 1 |
| 2 | 4 |
| 3 | 148 |
| 4 | 5821348 |
| 5 | 13748537282247342677718148 |
| 6 | 49900608324196518198677680899235165296598423281799348 |