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) |
|---|---|
| 1 | 0 |
| 2 | 9 |
| 3 | -18 |
| 4 | -162 |
| 5 | 2520 |
| 6 | 33192 |
| 7 | -1019088 |
| 8 | -7804944 |
| 9 | 723961728 |
| 10 | 2596523904 |
| 11 | -856142090496 |
| 12 | 6383648984832 |
| 13 | 1356696930401280 |
| 14 | -27667884260938752 |
| 15 | -2908030732698175488 |
| 16 | 122264703581556307968 |
| 17 | 7238339805811283361792 |