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 | 60 |
| 3 | 1410 |
| 4 | 62505 |
| 5 | 5284401 |
| 6 | 868838010 |
| 7 | 281703950040 |
| 8 | 181448450339760 |
| 9 | 232989133846286240 |
| 10 | 597389845561440183360 |
| 11 | 3061032714235774931187200 |
| 12 | 31357237236616342838622807040 |
| 13 | 642321739861948533960660029617920 |
| 14 | 26312068694834430629292373404100369920 |
| 15 | 2155589935049851254662487477552439610480640 |