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 | 3 |
| 1 | 11 |
| 2 | 49 |
| 3 | 251 |
| 4 | 1393 |
| 5 | 8051 |
| 6 | 47449 |
| 7 | 282251 |
| 8 | 1686433 |
| 9 | 10097891 |
| 10 | 60526249 |
| 11 | 362976251 |
| 12 | 2177317873 |
| 13 | 13062296531 |
| 14 | 78368963449 |
| 15 | 470199366251 |
| 16 | 2821153019713 |
| 17 | 16926788715971 |
| 18 | 101560344351049 |
| 19 | 609360902796251 |