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 | 45 |
| 2 | 1680 |
| 3 | 62790 |
| 4 | 2471175 |
| 5 | 104085135 |
| 6 | 4712781150 |
| 7 | 229345716600 |
| 8 | 11970744110325 |
| 9 | 668241679730625 |
| 10 | 39773331191493900 |
| 11 | 2516317288024790250 |
| 12 | 168723807382851595875 |
| 13 | 11956978164372003637875 |
| 14 | 893260022082269487896250 |
| 15 | 70178395183380972653665500 |