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) |
|---|---|
| 1 | 1 |
| 2 | 0 |
| 3 | 1 |
| 4 | 0 |
| 5 | -4 |
| 6 | 9 |
| 7 | 0 |
| 8 | 16 |
| 9 | -180 |
| 10 | 225 |
| 11 | 0 |
| 12 | -64 |
| 13 | 3024 |
| 14 | -12600 |
| 15 | 11025 |
| 16 | 0 |
| 17 | 256 |
| 18 | -48960 |
| 19 | 529200 |
| 20 | -1323000 |
| 21 | 893025 |
| 22 | 0 |
| 23 | -1024 |
| 24 | 785664 |
| 25 | -20275200 |
| 26 | 110602800 |
| 27 | -196465500 |
| 28 | 108056025 |
| 29 | 0 |
| 30 | 4096 |
| 31 | -12579840 |
| 32 | 749548800 |
| 33 | -8072064000 |
| 34 | 28605376800 |
| 35 | -39332393100 |
| 36 | 18261468225 |