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 | -10 |
| 2 | 35 |
| 3 | -50 |
| 4 | 95 |
| 5 | -502 |
| 6 | 1180 |
| 7 | -1420 |
| 8 | 4035 |
| 9 | -12860 |
| 10 | 22714 |
| 11 | -40930 |
| 12 | 98505 |
| 13 | -214720 |
| 14 | 435325 |
| 15 | -813962 |
| 16 | 1593055 |
| 17 | -3568600 |
| 18 | 6919100 |
| 19 | -12241860 |
| 20 | 24981909 |
| 21 | -50604940 |
| 22 | 93739535 |
| 23 | -174614840 |
| 24 | 334248255 |
| 25 | -644231302 |