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 | 0 |
| 2 | 0 |
| 3 | 0 |
| 4 | 1 |
| 5 | 0 |
| 6 | 0 |
| 7 | 16 |
| 8 | -18 |
| 9 | 0 |
| 10 | 252 |
| 11 | -576 |
| 12 | 423 |
| 13 | 3648 |
| 14 | -13344 |
| 15 | 19152 |
| 16 | 40294 |
| 17 | -259440 |
| 18 | 562020 |
| 19 | 95264 |
| 20 | -4307021 |
| 21 | 13303104 |
| 22 | -11632992 |
| 23 | -57973856 |
| 24 | 271183914 |
| 25 | -455166560 |
| 26 | -482496656 |
| 27 | 4831425864 |
| 28 | -12082047182 |
| 29 | 4185256128 |
| 30 | 73401528384 |
| 31 | -266390485184 |
| 32 | 330255999226 |
| 33 | 851455636352 |
| 34 | -5115138468772 |