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) |
|---|---|
| 9 | 1 |
| 10 | 9 |
| 11 | 90 |
| 12 | 825 |
| 13 | 7920 |
| 14 | 78507 |
| 15 | 813813 |
| 16 | 8828820 |
| 17 | 100321650 |
| 18 | 1193450830 |
| 19 | 14850852588 |
| 20 | 193081474872 |
| 21 | 2619543882540 |
| 22 | 37037407198050 |
| 23 | 545028468623100 |
| 24 | 8336937634715580 |
| 25 | 132393075623791785 |
| 26 | 2180112627147691500 |
| 27 | 37183793747600839625 |
| 28 | 656173638174834222300 |