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 | 4 |
| 2 | 46 |
| 3 | 138 |
| 4 | 690 |
| 5 | 197890 |
| 6 | 5444670 |
| 7 | 156719940 |
| 8 | 4941906970 |
| 9 | 135969743910 |