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 | 1 |
| 4 | 1 |
| 5 | 1 |
| 6 | 1 |
| 7 | 2 |
| 8 | -6 |
| 9 | 56 |
| 10 | -528 |
| 11 | 6193 |
| 12 | -86579 |
| 13 | 1425518 |
| 14 | -27298230 |
| 15 | 601580875 |
| 16 | -15116315766 |
| 17 | 429614643062 |
| 18 | -13711655205087 |
| 19 | 488332318973594 |
| 20 | -19296579341940067 |
| 21 | 841693047573682616 |
| 22 | -40338071854059455412 |
| 23 | 2115074863808199160561 |
| 24 | -120866265222965259346026 |