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 | 21 |
| 5 | 85 |
| 6 | 410 |
| 7 | 2366 |
| 8 | 16065 |
| 9 | 125665 |
| 10 | 1112074 |
| 11 | 10976174 |
| 12 | 119481285 |
| 13 | 1421542629 |
| 14 | 18348340114 |
| 15 | 255323504918 |
| 16 | 3809950976993 |
| 17 | 60683990530209 |
| 18 | 1027542662934898 |
| 19 | 18430998766219318 |
| 20 | 349096664728623317 |
| 21 | 6962409983976703317 |
| 22 | 145841989688186383338 |
| 23 | 3201192743180799343822 |