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 | -29 |
| 5 | 271 |
| 6 | 3091 |
| 7 | -61025 |
| 8 | -744029 |
| 9 | 34875871 |
| 10 | 211095331 |
| 11 | -37415273345 |
| 12 | 300267009571 |
| 13 | 61080483836191 |
| 14 | -2133136977892829 |
| 15 | -119576844586022465 |
| 16 | 11752559492568148771 |
| 17 | 94348367247493654111 |
| 18 | -68793303669649907424989 |
| 19 | 2764486881197709482575615 |