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 | -3 |
| 3 | 13 |
| 4 | -67 |
| 5 | 379 |
| 6 | -2267 |
| 7 | 14065 |
| 8 | -89515 |
| 9 | 580379 |
| 10 | -3815731 |
| 11 | 25356051 |
| 12 | -169898467 |
| 13 | 1145825123 |
| 14 | -7767073859 |
| 15 | 52858784539 |
| 16 | -360823702851 |
| 17 | 2468606626813 |
| 18 | -16915880702563 |
| 19 | 116028193869805 |
| 20 | -796200367684945 |
| 21 | 5463239318586601 |
| 22 | -37465765826805457 |
| 23 | 256664142145450777 |
| 24 | -1755608165010431139 |