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 | 50 |
| 3 | 1684 |
| 4 | 146946 |
| 5 | 33635880 |
| 6 | 21062625664 |
| 7 | 37432954261477 |