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 | 77 |
| 2 | 2926 |
| 3 | 73150 |
| 4 | 1353275 |
| 5 | 19757815 |
| 6 | 237093780 |
| 7 | 2404808340 |
| 8 | 21042072975 |
| 9 | 161322559475 |
| 10 | 1096993404430 |
| 11 | 6681687099710 |
| 12 | 36749279048405 |
| 13 | 183746395242025 |
| 14 | 839983521106400 |
| 15 | 3527930788646880 |
| 16 | 13670731806006660 |
| 17 | 49053802362729780 |
| 18 | 163512674542432600 |