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 | 1 |
| 2 | -5 |
| 3 | -32 |
| 4 | 112 |
| 5 | 2212 |
| 6 | -5348 |
| 7 | -292880 |
| 8 | 276976 |
| 9 | 64180144 |
| 10 | 60400144 |
| 11 | -21123205376 |
| 12 | -68151050240 |
| 13 | 9766562233792 |
| 14 | 57568265355328 |
| 15 | -6044149831446272 |
| 16 | -54001800190537472 |
| 17 | 4827069458763086080 |
| 18 | 59568915131392086784 |
| 19 | -4835221290238425841664 |
| 20 | -77896195282519949963264 |