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) |
|---|---|
| 2 | 1 |
| 3 | -9 |
| 4 | 87 |
| 5 | -975 |
| 6 | 12657 |
| 7 | -188090 |
| 8 | 3159699 |
| 9 | -59326371 |
| 10 | 1232843529 |
| 11 | -28116615263 |
| 12 | 698649506871 |
| 13 | -18796044698977 |
| 14 | 544507930693022 |
| 15 | -16903759793180115 |
| 16 | 559960766050363931 |
| 17 | -19719027513960290370 |
| 18 | 735696883534117583082 |
| 19 | -28991986984973263419262 |