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) |
|---|---|
| 1 | 1 |
| 2 | 2 |
| 3 | 5 |
| 4 | 16 |
| 5 | 55 |
| 6 | 225 |
| 7 | 949 |
| 8 | 4269 |
| 9 | 19500 |
| 10 | 91115 |
| 11 | 429742 |
| 12 | 2047660 |
| 13 | 9820197 |
| 14 | 47383255 |
| 15 | 229725560 |
| 16 | 1118568692 |
| 17 | 5466616025 |
| 18 | 26804560282 |
| 19 | 131817042605 |
| 20 | 649952289243 |