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 | -7 |
| 3 | 74 |
| 4 | -820 |
| 5 | 10196 |
| 6 | -134785 |
| 7 | 1860668 |
| 8 | -26508457 |
| 9 | 386843804 |
| 10 | -5753126477 |
| 11 | 86878155652 |
| 12 | -1328593620692 |
| 13 | 20533664196478 |
| 14 | -320220157730975 |
| 15 | 5032648114664896 |
| 16 | -79629405527982623 |
| 17 | 1267425784159379572 |
| 18 | -20279086501234998596 |
| 19 | 325989622456860054852 |