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 | 5 |
| 2 | -6 |
| 3 | -139 |
| 4 | 1654 |
| 5 | -5853 |
| 6 | -196860 |
| 7 | 6258751 |
| 8 | -112580442 |
| 9 | 985287863 |
| 10 | 26443436876 |
| 11 | -1897380617625 |
| 12 | 72596047613116 |
| 13 | -2086036395460171 |
| 14 | 39493340495025864 |
| 15 | 304974352009838745 |
| 16 | -85532651616832374010 |
| 17 | 6040114369000387188975 |
| 18 | -321378391411642082323524 |
| 19 | 14224299551865677212271567 |