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 | -5 |
| 4 | 7 |
| 5 | 71 |
| 6 | -59 |
| 7 | -1511 |
| 8 | -9295 |
| 9 | -1583 |
| 10 | 861751 |
| 11 | 4039091 |
| 12 | -80670281 |
| 13 | -606807785 |
| 14 | 7674244397 |
| 15 | 78614840641 |
| 16 | 1146707474401 |
| 17 | 12874145737889 |
| 18 | -1054507266321425 |
| 19 | -19048413877999253 |
| 20 | 238097060642380391 |
| 21 | 6646823785301856871 |
| 22 | -59731575523361439851 |
| 23 | -2231444370433747995415 |