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 | 3 |
| 2 | -5 |
| 3 | 81 |
| 4 | -462 |
| 5 | 385 |
| 6 | 30375 |
| 7 | -369603 |
| 8 | 765765 |
| 9 | -425425 |
| 10 | 4465125 |
| 11 | -94121676 |
| 12 | 349922430 |
| 13 | -446185740 |
| 14 | 185910725 |
| 15 | 1519035525 |
| 16 | -49286948607 |
| 17 | 284499769554 |
| 18 | -614135872350 |
| 19 | 566098157625 |
| 20 | -188699385875 |