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 | 2 |
| 4 | 3 |
| 5 | 8 |
| 6 | 17 |
| 7 | 39 |
| 8 | 126 |
| 9 | 352 |
| 10 | 1026 |
| 11 | 2943 |
| 12 | 11429 |
| 13 | 39138 |
| 14 | 138903 |
| 15 | 486490 |
| 16 | 1711141 |
| 17 | 7720713 |
| 18 | 31383260 |
| 19 | 131236182 |
| 20 | 543056039 |
| 21 | 2254646235 |
| 22 | 9349845765 |
| 23 | 48137959377 |
| 24 | 226341090088 |
| 25 | 1090094720010 |
| 26 | 5203693239201 |
| 27 | 24909594299924 |