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 | 19 |
| 4 | 73 |
| 5 | 901 |
| 6 | 7921 |
| 7 | 88831 |
| 8 | 1261009 |
| 9 | 15786793 |
| 10 | 284515201 |
| 11 | 4359416491 |
| 12 | 88359404761 |
| 13 | 1671036171949 |
| 14 | 36734936604913 |
| 15 | 831051144091351 |
| 16 | 19848996799904161 |
| 17 | 516144198653004241 |
| 18 | 13522792578340917889 |
| 19 | 391107276466207593283 |
| 20 | 11295497154349628317801 |