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) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 1 |
| 3 | -11 |
| 4 | -47 |
| 5 | -39 |
| 6 | 1681 |
| 7 | 10893 |
| 8 | -13215 |
| 9 | -851471 |
| 10 | -5515679 |
| 11 | 34375397 |
| 12 | 887687857 |
| 13 | 3982645577 |
| 14 | -85350572943 |
| 15 | -1466457337859 |
| 16 | -659043831871 |
| 17 | 270733024430305 |
| 18 | 3181606182917569 |
| 19 | -24432689736388395 |
| 20 | -1076204061663657839 |
| 21 | -6834631528147762247 |
| 22 | 221729710998069153617 |