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 | 0 |
| 1 | 1 |
| 2 | 2 |
| 3 | 3 |
| 4 | 4 |
| 5 | -5 |
| 6 | -24 |
| 7 | -98 |
| 8 | -272 |
| 9 | 621 |
| 10 | 4960 |
| 11 | 31856 |
| 12 | 132672 |
| 13 | -437593 |
| 14 | -4893056 |
| 15 | -42854160 |
| 16 | -237969664 |
| 17 | 1026405753 |
| 18 | 14756156928 |
| 19 | 163699919104 |
| 20 | 1136284574720 |
| 21 | -6054175060941 |
| 22 | -106379840985088 |
| 23 | -1428593836836352 |
| 24 | -11899498670002176 |
| 25 | 75477454065058725 |