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 | 20 |
| 5 | 76 |
| 6 | 300 |
| 7 | 1252 |
| 8 | 5324 |
| 9 | 22869 |
| 10 | 98497 |
| 11 | 426139 |
| 12 | 1850782 |
| 13 | 8067832 |
| 14 | 35280090 |
| 15 | 154696678 |
| 16 | 679891308 |
| 17 | 2994160190 |
| 18 | 13209317445 |
| 19 | 58367173629 |
| 20 | 258266895944 |
| 21 | 1144247729578 |
| 22 | 5075406674186 |
| 23 | 22535970467972 |
| 24 | 100160698537196 |