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 | 3 |
| 2 | 19 |
| 3 | 177 |
| 4 | 2201 |
| 5 | 34203 |
| 6 | 637819 |
| 7 | 13876377 |
| 8 | 345022001 |
| 9 | 9650948403 |
| 10 | 299951259619 |
| 11 | 10254726248577 |
| 12 | 382459993625801 |
| 13 | 15452902408998603 |
| 14 | 672386203441625419 |
| 15 | 31346622138810396777 |
| 16 | 1558803698602736533601 |
| 17 | 82360892667114765064803 |
| 18 | 4607594447779876771255219 |