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 | 2 |
| 3 | 6 |
| 4 | 25 |
| 5 | 138 |
| 6 | 970 |
| 7 | 8390 |
| 8 | 86796 |
| 9 | 1049546 |
| 10 | 14563135 |
| 11 | 228448504 |
| 12 | 4002300038 |
| 13 | 77523038603 |
| 14 | 1646131568618 |
| 15 | 38043008887356 |
| 16 | 950967024783228 |
| 17 | 25573831547118764 |
| 18 | 736404945614783668 |
| 19 | 22611026430036582671 |