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) |
|---|---|
| 0 | 1 |
| 1 | 6 |
| 2 | 29 |
| 3 | 126 |
| 4 | 513 |
| 5 | 1998 |
| 6 | 7533 |
| 7 | 27702 |
| 8 | 99873 |
| 9 | 354294 |
| 10 | 1240029 |
| 11 | 4290894 |
| 12 | 14703201 |
| 13 | 49955454 |
| 14 | 168466797 |
| 15 | 564390342 |
| 16 | 1879706817 |
| 17 | 6227425638 |
| 18 | 20533285917 |
| 19 | 67411165086 |
| 20 | 220442258241 |
| 21 | 718277586606 |
| 22 | 2332658764269 |
| 23 | 7552375012566 |