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 | 4 |
| 2 | 40 |
| 3 | -544 |
| 4 | -14240 |
| 5 | 240512 |
| 6 | 7905536 |
| 7 | -144081920 |
| 8 | -5248825856 |
| 9 | 99459618816 |
| 10 | 3842132979712 |
| 11 | -74547398033408 |
| 12 | -2991092285194240 |
| 13 | 58965437254402048 |
| 14 | 2429529032173420544 |
| 15 | -48445417122664284160 |
| 16 | -2035619492638819483648 |
| 17 | 40941665274780773253120 |