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 | -7 |
| 3 | 53 |
| 4 | 497 |
| 5 | -147 |
| 6 | -44055 |
| 7 | -437339 |
| 8 | 971745 |
| 9 | 90858205 |
| 10 | 1254551513 |
| 11 | -56188139 |
| 12 | -361749699119 |
| 13 | -7793811482035 |
| 14 | -47717641321527 |
| 15 | 2053219888651909 |
| 16 | 77548473901557697 |
| 17 | 1171383881442334141 |
| 18 | -8155337883596701767 |