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 | 3 |
| 3 | 11 |
| 4 | 45 |
| 5 | 185 |
| 6 | 756 |
| 7 | 3084 |
| 8 | 12580 |
| 9 | 51320 |
| 10 | 209365 |
| 11 | 854126 |
| 12 | 3484490 |
| 13 | 14215310 |
| 14 | 57992715 |
| 15 | 236586825 |
| 16 | 965178576 |
| 17 | 3937538296 |
| 18 | 16063564001 |
| 19 | 65532845396 |
| 20 | 267347509271 |
| 21 | 1090669728772 |
| 22 | 4449491452173 |
| 23 | 18152125855049 |
| 24 | 74053333195325 |
| 25 | 302107654008601 |
| 26 | 1232477063116753 |