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 | 0 |
| 2 | -3 |
| 3 | 40 |
| 4 | -515 |
| 5 | 7056 |
| 6 | -102935 |
| 7 | 1554288 |
| 8 | -22775319 |
| 9 | 265497760 |
| 10 | 586651461 |
| 11 | -230587852560 |
| 12 | 13426823564869 |
| 13 | -637734419560224 |
| 14 | 28594259589697425 |
| 15 | -1264238490602458784 |
| 16 | 56015489395280490385 |
| 17 | -2499557487903373341888 |
| 18 | 112150411888789509887053 |