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) |
|---|---|
| 4 | 2 |
| 5 | 28 |
| 6 | 236 |
| 7 | 1852 |
| 8 | 14622 |
| 9 | 119964 |
| 10 | 1034992 |
| 11 | 9434444 |
| 12 | 90968602 |
| 13 | 927367340 |
| 14 | 9982234068 |
| 15 | 113261721276 |
| 16 | 1352111669942 |
| 17 | 16950982295356 |
| 18 | 222752212005464 |
| 19 | 3062768908594348 |
| 20 | 43987314357078642 |
| 21 | 658804420084315212 |