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 | -1 |
| 2 | 3 |
| 3 | -14 |
| 4 | 195 |
| 5 | -924 |
| 6 | 267995 |
| 7 | -164604 |
| 8 | 45886995 |
| 9 | -519348280 |
| 10 | 843061472253 |
| 11 | -33644021190 |
| 12 | 19713207603254165 |
| 13 | -29447897812956 |
| 14 | 7112683552535920515 |
| 15 | -219530334327028402216 |
| 16 | 2896662162807666940995 |
| 17 | -59209706525969052144 |
| 18 | 63061212713478261338180955809 |
| 19 | -124888410979403015484540 |