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 | -2 |
| 2 | 14 |
| 3 | -176 |
| 4 | 2615 |
| 5 | -42444 |
| 6 | 734310 |
| 7 | -13332898 |
| 8 | 251087228 |
| 9 | -4863520344 |
| 10 | 96340129818 |
| 11 | -1943639738074 |
| 12 | 39815238143374 |
| 13 | -826201916477272 |
| 14 | 17334983283537509 |
| 15 | -367213838120451038 |
| 16 | 7844257467257818627 |
| 17 | -168807941163188191336 |
| 18 | 3656662240133060807499 |
| 19 | -79675906058698383705100 |