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 | 3 |
| 3 | 15 |
| 4 | 126 |
| 5 | 1667 |
| 6 | 31966 |
| 7 | 828678 |
| 8 | 27535826 |
| 9 | 1128945382 |
| 10 | 55473589278 |
| 11 | 3193471420236 |
| 12 | 211517309562652 |