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) |
|---|---|
| 2 | 1 |
| 3 | 2 |
| 4 | 32 |
| 5 | 128 |
| 6 | 512 |
| 7 | 8192 |
| 8 | 2097152 |
| 9 | 226492416 |
| 10 | 301989888 |
| 11 | 536870912 |
| 12 | 32212254720 |
| 13 | 8349416423424 |
| 14 | 4453022092492800 |
| 15 | 1122161567308185600 |
| 16 | 2294196982052290560 |
| 17 | 12235717237612216320 |
| 18 | 16314289650149621760 |
| 19 | 58731442740538638336000 |
| 20 | 51166832915557261718323200 |