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 | 4 |
| 2 | 24 |
| 3 | 208 |
| 4 | 2208 |
| 5 | 28864 |
| 6 | 440064 |
| 7 | 7752448 |
| 8 | 153604608 |
| 9 | 3398247424 |
| 10 | 82812002304 |
| 11 | 2208100261888 |
| 12 | 63835179614208 |
| 13 | 1991789102301184 |
| 14 | 66630050985836544 |
| 15 | 2381273427126550528 |
| 16 | 90474637735806763008 |
| 17 | 3643995535114567942144 |
| 18 | 154996077159081295478784 |
| 19 | 6946094284451252292026368 |