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 | 6 |
| 2 | -15 |
| 3 | 90 |
| 4 | -660 |
| 5 | 5310 |
| 6 | -45765 |
| 7 | 413640 |
| 8 | -3864345 |
| 9 | 37014120 |
| 10 | -361577790 |
| 11 | 3588484140 |
| 12 | -36079979085 |
| 13 | 366728363460 |
| 14 | -3762120325140 |
| 15 | 38901621985290 |
| 16 | -405039437707575 |
| 17 | 4242802537386450 |
| 18 | -44681704461745740 |
| 19 | 472795814216587140 |
| 20 | -5024232597805717410 |
| 21 | 53596341229925979360 |
| 22 | -573736849659978481665 |
| 23 | 6161218734911098973490 |
| 24 | -66355728143871653462745 |