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 | 2 |
| 3 | 4 |
| 4 | 9 |
| 5 | 19 |
| 6 | 37 |
| 7 | 52 |
| 8 | -25 |
| 9 | -630 |
| 10 | -3616 |
| 11 | -15897 |
| 12 | -61476 |
| 13 | -215135 |
| 14 | -677464 |
| 15 | -1823081 |
| 16 | -3389900 |
| 17 | 2523349 |
| 18 | 73121734 |
| 19 | 526205851 |
| 20 | 2914005085 |
| 21 | 14163375846 |
| 22 | 62788424920 |
| 23 | 255900158756 |
| 24 | 945473736954 |
| 25 | 3008738746058 |
| 26 | 6827204137454 |
| 27 | -2853842162077 |
| 28 | -171206510083289 |