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 | -2 |
| 2 | 0 |
| 3 | 4 |
| 4 | 32 |
| 5 | 48 |
| 6 | -608 |
| 7 | -6400 |
| 8 | -24064 |
| 9 | 163072 |
| 10 | 3567104 |
| 11 | 28394496 |
| 12 | 6535168 |
| 13 | -3250745344 |
| 14 | -50725740544 |
| 15 | -344530853888 |
| 16 | 2476610551808 |
| 17 | 110057610608640 |
| 18 | 1655672654135296 |
| 19 | 9616664975114240 |
| 20 | -195178079811272704 |
| 21 | -6998474114188967936 |
| 22 | -110894925369151848448 |