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 | 6 |
| 4 | 25 |
| 5 | 137 |
| 6 | 945 |
| 7 | 7927 |
| 8 | 78731 |
| 9 | 906705 |
| 10 | 11908357 |
| 11 | 175978520 |
| 12 | 2893866042 |
| 13 | 52467157456 |
| 14 | 1040596612520 |
| 15 | 22425725219277 |
| 16 | 522102436965475 |
| 17 | 13064892459014192 |
| 18 | 349829488635512316 |