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 | 2 |
| 2 | 2 |
| 3 | 20 |
| 4 | 6 |
| 5 | 108 |
| 6 | 148 |
| 7 | 776 |
| 8 | -186 |
| 9 | 5964 |
| 10 | -4 |
| 11 | 51032 |
| 12 | -89700 |
| 13 | 512120 |
| 14 | -1259416 |
| 15 | 6406032 |
| 16 | -19733434 |
| 17 | 78363148 |
| 18 | -268823572 |
| 19 | 1047941688 |
| 20 | -3800035916 |
| 21 | 14327505832 |
| 22 | -52766730600 |
| 23 | 199492430192 |
| 24 | -746479735524 |
| 25 | 2811936761016 |
| 26 | -10588174502568 |
| 27 | 40092283176560 |
| 28 | -151796846803592 |