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 | 1 |
| 2 | -2 |
| 3 | 30 |
| 4 | -268 |
| 5 | 3130 |
| 6 | -46470 |
| 7 | 823550 |
| 8 | -16781368 |
| 9 | 387421227 |
| 10 | -9999900090 |
| 11 | 285311670622 |
| 12 | -8916103453380 |
| 13 | 302875106592266 |
| 14 | -11112006720144694 |
| 15 | 437893890381622140 |
| 16 | -18446744078004584688 |
| 17 | 827240261886336764194 |
| 18 | -39346408075098212291754 |
| 19 | 1978419655660313589123998 |