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 | -31 |
| 2 | 465 |
| 3 | -4526 |
| 4 | 32426 |
| 5 | -184357 |
| 6 | 877052 |
| 7 | -3633851 |
| 8 | 13513458 |
| 9 | -46099108 |
| 10 | 146495398 |
| 11 | -438514468 |
| 12 | 1246964119 |
| 13 | -3391183930 |
| 14 | 8867709030 |
| 15 | -22393552057 |
| 16 | 54808232438 |
| 17 | -130404256148 |
| 18 | 302394884204 |
| 19 | -684929956630 |
| 20 | 1518203338688 |