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 | 0 |
| 3 | 0 |
| 4 | 0 |
| 5 | 1 |
| 6 | -15 |
| 7 | 175 |
| 8 | -1960 |
| 9 | 22449 |
| 10 | -269073 |
| 11 | 3403070 |
| 12 | -45510630 |
| 13 | 643152796 |
| 14 | -9586136560 |
| 15 | 150319669136 |
| 16 | -2473024029840 |
| 17 | 42562037379744 |
| 18 | -764017130370276 |
| 19 | 14260496108114340 |
| 20 | -275877454002406236 |
| 21 | 5512350021871343616 |
| 22 | -113318466860425703184 |