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 | 5 |
| 4 | 15 |
| 5 | 52 |
| 6 | 205 |
| 7 | 917 |
| 8 | 4658 |
| 9 | 26817 |
| 10 | 173899 |
| 11 | 1257916 |
| 12 | 10036409 |
| 13 | 87351977 |
| 14 | 821268402 |
| 15 | 8273013085 |
| 16 | 88696718215 |
| 17 | 1006586902196 |
| 18 | 12037812901733 |
| 19 | 151136735414301 |
| 20 | 1985815346287906 |