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 | 5 |
| 2 | 14 |
| 3 | 30 |
| 4 | 140 |
| 5 | 1240 |
| 6 | 4900 |
| 7 | 10416 |
| 8 | 85344 |
| 9 | 173880 |
| 10 | 1801800 |
| 11 | 5559680 |
| 12 | 44608256 |
| 13 | 357389824 |
| 14 | 44870400 |
| 15 | 110099203200 |
| 16 | 2861214720 |
| 17 | 98269966080 |
| 18 | 982218617856 |
| 19 | 1466149724160 |
| 20 | 11727587164160 |
| 21 | 243912389529600 |
| 22 | 750591347982336 |
| 23 | 1951282875801600 |
| 24 | 37635982963937280 |
| 25 | 460962807482777600 |