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 | 3 |
| 3 | -9 |
| 4 | 0 |
| 5 | 81 |
| 6 | -171 |
| 7 | -621 |
| 8 | 3672 |
| 9 | 324 |
| 10 | -54918 |
| 11 | 125145 |
| 12 | 563922 |
| 13 | -3381345 |
| 14 | -1013553 |
| 15 | 59036607 |
| 16 | -128956455 |
| 17 | -693917604 |
| 18 | 3979050642 |
| 19 | 2186515944 |
| 20 | -76048363647 |
| 21 | 153593093106 |
| 22 | 978492895848 |
| 23 | -5278059507771 |
| 24 | -4343581909296 |
| 25 | 107892778958370 |
| 26 | -197193416230692 |