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) |
|---|---|
| 1 | 2 |
| 2 | -1 |
| 3 | -78 |
| 4 | 880 |
| 5 | -4656 |
| 6 | -14304 |
| 7 | -423936 |
| 8 | 8342720 |
| 9 | 711956736 |
| 10 | -615707136 |
| 11 | 21057138688 |
| 12 | -4663930678272 |
| 13 | 211912980656128 |
| 14 | -9178450735677440 |
| 15 | 40005919124799488 |
| 16 | 83013253447139328 |
| 17 | -8525111273818357760 |
| 18 | -800258888289188708352 |
| 19 | -15170733077495639179264 |