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 | 0 |
| 3 | 0 |
| 4 | 0 |
| 5 | 0 |
| 6 | 1 |
| 7 | 5040 |
| 8 | 187530840 |
| 9 | 12025780892160 |
| 10 | 1289144584143523800 |
| 11 | 226885231700215713535680 |
| 12 | 64051375889927380035549804336 |
| 13 | 28278447454165011203551734584421120 |