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 | 2 |
| 3 | 9 |
| 4 | 54 |
| 5 | 448 |
| 6 | 4650 |
| 7 | 53611 |
| 8 | 655033 |
| 9 | 8259635 |
| 10 | 106371085 |
| 11 | 1391032357 |
| 12 | 18412269694 |