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) |
|---|---|
| 1 | 0 |
| 2 | 24 |
| 3 | 840 |
| 4 | 47640 |
| 5 | 5419992 |
| 6 | 1328460312 |
| 7 | 725187096504 |
| 8 | 897937832100888 |
| 9 | 2550310193527246056 |
| 10 | 16737195174968513278656 |
| 11 | 255111495114527014241534160 |
| 12 | 9064348272085612349020943764248 |
| 13 | 752834148761621410865592159869765856 |