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 | 1 |
| 2 | 3 |
| 3 | 19 |
| 4 | 233 |
| 5 | 4851 |
| 6 | 158175 |
| 7 | 7724333 |
| 8 | 550898367 |
| 9 | 56536880923 |
| 10 | 8267519506789 |
| 11 | 1709320029453719 |
| 12 | 496139872875425839 |
| 13 | 200807248677750187825 |
| 14 | 112602879608997769049739 |
| 15 | 86955243134629606109442219 |
| 16 | 91962123875462441868790125305 |
| 17 | 132524871920295877733718959290203 |
| 18 | 259048612476248175744581063815546423 |