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 | 3 |
| 4 | 11 |
| 5 | 23 |
| 6 | 73 |
| 7 | 211 |
| 8 | 651 |
| 9 | 2371 |
| 10 | 7401 |
| 11 | 30151 |
| 12 | 107713 |
| 13 | 456409 |
| 14 | 1888753 |
| 15 | 8148451 |
| 16 | 37754791 |
| 17 | 170459451 |
| 18 | 842310755 |
| 19 | 4096595827 |
| 20 | 20984546901 |