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 | 1 |
| 2 | 4 |
| 3 | 27 |
| 4 | 250 |
| 5 | 2915 |
| 6 | 40766 |
| 7 | 662494 |
| 8 | 12236190 |
| 9 | 252664815 |
| 10 | 5759288044 |
| 11 | 143463453199 |
| 12 | 3873471153366 |
| 13 | 112587628893480 |