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 | -3 |
| 3 | 8 |
| 4 | 13 |
| 5 | -51 |
| 6 | -120 |
| 7 | 538 |
| 8 | 781 |
| 9 | -5419 |
| 10 | -3053 |
| 11 | 47673 |
| 12 | 5080 |
| 13 | -427740 |
| 14 | 136462 |
| 15 | 3922383 |
| 16 | -3278067 |
| 17 | -34819588 |
| 18 | 48561567 |
| 19 | 299316651 |
| 20 | -603368637 |
| 21 | -2509708844 |
| 22 | 6948730643 |
| 23 | 20210062532 |
| 24 | -76150197416 |
| 25 | -152569240051 |
| 26 | 801154765564 |
| 27 | 1039352472008 |
| 28 | -8158396721266 |