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 | 1 |
| 2 | -3 |
| 3 | -39 |
| 4 | 1989 |
| 5 | 407745 |
| 6 | -333943155 |
| 7 | -1094331718935 |
| 8 | 14343405840081045 |
| 9 | 752010424789609108305 |
| 10 | -157707866234752874148183075 |
| 11 | -132294978377551030760819002477575 |
| 12 | 443908259132104963309174796130361690725 |
| 13 | 5958035886896289829709072930982993020807155425 |