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 | 1 |
| 2 | 1 |
| 3 | -3 |
| 4 | 11 |
| 5 | 38 |
| 6 | 249 |
| 7 | -2357 |
| 8 | 8767 |
| 9 | 496035 |
| 10 | -3769372 |
| 11 | -299154043 |
| 12 | -12064147359 |
| 13 | 632926474117 |
| 14 | -65604679199921 |
| 15 | -6662962874355342 |
| 16 | -720710377683595651 |
| 17 | 285131375126739646739 |
| 18 | 5206174703484724719135 |