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) |
|---|---|
| 10 | 1 |
| 11 | 126 |
| 12 | 7008 |
| 13 | 261648 |
| 14 | 7826544 |
| 15 | 205083936 |
| 16 | 4944057984 |
| 17 | 112834665216 |
| 18 | 2481031718144 |
| 19 | 53154302311936 |
| 20 | 1117907385569280 |
| 21 | 23198258406862848 |
| 22 | 476700713349279744 |
| 23 | 9725111087129763840 |
| 24 | 197341040692081557504 |
| 25 | 3988586127032474271744 |
| 26 | 80380982576880196780032 |
| 27 | 1616460856969040046850048 |
| 28 | 32457783381454315268866048 |