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 | -3 |
| 2 | -4 |
| 3 | 99 |
| 4 | 116 |
| 5 | -2523 |
| 6 | -8764 |
| 7 | 1074243 |
| 8 | 1242356 |
| 9 | -48982293 |
| 10 | -283202524 |
| 11 | 27296351769 |
| 12 | 94690800596 |
| 13 | -5393115879063 |
| 14 | -43653497804284 |
| 15 | 22950350777886291 |
| 16 | 26538141745926836 |
| 17 | -1976553215554138833 |
| 18 | -20569900661155862044 |
| 19 | 3424560766779704633439 |
| 20 | 19799583458238177373076 |