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 | -20 |
| 2 | 508 |
| 3 | -17544 |
| 4 | 808848 |
| 5 | -48405888 |
| 6 | 3663035136 |
| 7 | -342678781440 |
| 8 | 38879803008000 |
| 9 | -5263815891456000 |
| 10 | 838682139211776000 |
| 11 | -155393459730173952000 |
| 12 | 33136711787903754240000 |
| 13 | -8059211591488628981760000 |
| 14 | 2217755736675770074398720000 |