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) |
|---|---|
| 2 | -1 |
| 3 | 51 |
| 4 | -10594 |
| 5 | 356487 |
| 6 | -101141295 |
| 7 | 48350824787 |
| 8 | -2405967772180 |
| 9 | 5296878246375849 |
| 10 | -24680641353374049205 |
| 11 | 12431632076904547636178 |
| 12 | -34807634670487142385955264 |
| 13 | 5037797143580320963623681605 |