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 | 1 |
| 3 | 2 |
| 4 | 5 |
| 5 | 12 |
| 6 | 39 |
| 7 | 123 |
| 8 | 412 |
| 9 | 1431 |
| 10 | 4831 |
| 11 | 17363 |
| 12 | 60697 |
| 13 | 219777 |
| 14 | 781260 |
| 15 | 2858031 |
| 16 | 10329091 |
| 17 | 38103069 |
| 18 | 138996792 |