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 | 0 |
| 1 | 0 |
| 2 | 50 |
| 3 | 750 |
| 4 | 7500 |
| 5 | 62500 |
| 6 | 468750 |
| 7 | 3281250 |
| 8 | 21875000 |
| 9 | 140625000 |
| 10 | 878906250 |
| 11 | 5371093750 |
| 12 | 32226562500 |
| 13 | 190429687500 |
| 14 | 1110839843750 |
| 15 | 6408691406250 |
| 16 | 36621093750000 |
| 17 | 207519531250000 |
| 18 | 1167297363281250 |
| 19 | 6523132324218750 |