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 | 0 |
| 2 | -3 |
| 3 | -3 |
| 4 | 21 |
| 5 | 54 |
| 6 | -157 |
| 7 | -828 |
| 8 | 816 |
| 9 | 11684 |
| 10 | 5352 |
| 11 | -151407 |
| 12 | -288759 |
| 13 | 1737498 |
| 14 | 6671607 |
| 15 | -15789371 |
| 16 | -122051205 |
| 17 | 58021488 |
| 18 | 1935857500 |
| 19 | 1977087345 |
| 20 | -26913144267 |
| 21 | -70826569596 |
| 22 | 314853424458 |
| 23 | 1586212109946 |
| 24 | -2594198888498 |
| 25 | -29124507344868 |
| 26 | -2575010176581 |