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 | 2 |
| 2 | 7 |
| 3 | 23 |
| 4 | 72 |
| 5 | 221 |
| 6 | 669 |
| 7 | 2014 |
| 8 | 6050 |
| 9 | 18159 |
| 10 | 54487 |
| 11 | 163472 |
| 12 | 490428 |
| 13 | 1471297 |
| 14 | 4413905 |
| 15 | 13241730 |
| 16 | 39725206 |
| 17 | 119175635 |
| 18 | 357526923 |