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 | -1025 |
| 3 | 59050 |
| 4 | -1047553 |
| 5 | 9765626 |
| 6 | -60526250 |
| 7 | 282475250 |
| 8 | -1072692225 |
| 9 | 3486843451 |
| 10 | -10009766650 |
| 11 | 25937424602 |
| 12 | -61858004650 |
| 13 | 137858491850 |
| 14 | -289537131250 |
| 15 | 576660215300 |
| 16 | -1098436836353 |
| 17 | 2015993900450 |
| 18 | -3574014537275 |
| 19 | 6131066257802 |