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 | 1 |
| 2 | 0 |
| 3 | -8 |
| 4 | -34 |
| 5 | -74 |
| 6 | 0 |
| 7 | 736 |
| 8 | 3334 |
| 9 | 7606 |
| 10 | 0 |
| 11 | -80464 |
| 12 | -372436 |
| 13 | -864772 |
| 14 | 0 |
| 15 | 9400192 |
| 16 | 43976774 |
| 17 | 103061158 |
| 18 | 0 |
| 19 | -1137528688 |
| 20 | -5355697084 |
| 21 | -12623082284 |
| 22 | 0 |
| 23 | 140697113792 |
| 24 | 665238165916 |
| 25 | 1574005263676 |
| 26 | 0 |
| 27 | -17663830073504 |
| 28 | -83769667651816 |
| 29 | -198760191043784 |
| 30 | 0 |