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 | -50 |
| 3 | -500 |
| 4 | -6875 |
| 5 | -110000 |
| 6 | -1925000 |
| 7 | -35750000 |
| 8 | -692656250 |
| 9 | -13853125000 |
| 10 | -283989062500 |
| 11 | -5937953125000 |
| 12 | -126181503906250 |
| 13 | -2717755468750000 |
| 14 | -59208244140625000 |
| 15 | -1302581371093750000 |