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 | 4 |
| 4 | -7 |
| 5 | 0 |
| 6 | 13 |
| 7 | 10 |
| 8 | -92 |
| 9 | 21 |
| 10 | 720 |
| 11 | -2019 |
| 12 | 1193 |
| 13 | 6281 |
| 14 | -18054 |
| 15 | 16111 |
| 16 | 11059 |
| 17 | -14653 |
| 18 | -57685 |
| 19 | -86620 |
| 20 | 1281406 |
| 21 | -3454742 |
| 22 | 2383734 |
| 23 | 9409968 |
| 24 | -30397071 |
| 25 | 43327680 |
| 26 | -56130326 |
| 27 | 128981571 |
| 28 | -73487834 |
| 29 | -1219918457 |
| 30 | 5059678044 |
| 31 | -7826243881 |
| 32 | -4131571113 |
| 33 | 38850603452 |