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 | -100 |
| 4 | 556 |
| 5 | 8312 |
| 6 | -33416 |
| 7 | -964528 |
| 8 | 2281360 |
| 9 | 143454752 |
| 10 | -82670816 |
| 11 | -25987196992 |
| 12 | -35605572416 |
| 13 | 5542023405440 |
| 14 | 19415750756224 |
| 15 | -1357758396658432 |
| 16 | -7957769497497344 |
| 17 | 375118879242633728 |
| 18 | 3185315224719454720 |
| 19 | -115167886425174418432 |
| 20 | -1319713579704402351104 |