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 | -2 |
| 3 | 0 |
| 4 | -32 |
| 5 | 0 |
| 6 | -704 |
| 7 | 0 |
| 8 | -54784 |
| 9 | 0 |
| 10 | -2610176 |
| 11 | 0 |
| 12 | -10976325632 |
| 13 | 0 |
| 14 | -52971659264 |
| 15 | 0 |
| 16 | -179326416191488 |
| 17 | 0 |
| 18 | -24309257264168960 |
| 19 | 0 |
| 20 | -69389116291423404032 |
| 21 | 0 |
| 22 | -8404514249426618810368 |
| 23 | 0 |
| 24 | -81520321871322828385550336 |
| 25 | 0 |
| 26 | -438807077783516207378333696 |
| 27 | 0 |
| 28 | -690781531822985516802849636352 |