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 | 1 |
| 3 | 1 |
| 4 | 2 |
| 5 | 3 |
| 6 | 7 |
| 7 | 18 |
| 8 | 48 |
| 9 | 133 |
| 10 | 373 |
| 11 | 1054 |
| 12 | 3011 |
| 13 | 8678 |
| 14 | 25216 |
| 15 | 73801 |
| 16 | 217476 |
| 17 | 644554 |
| 18 | 1920718 |
| 19 | 5750807 |
| 20 | 17293653 |
| 21 | 52208550 |
| 22 | 158179651 |
| 23 | 480806995 |
| 24 | 1465841157 |
| 25 | 4481166838 |
| 26 | 13733815975 |
| 27 | 42189399220 |
| 28 | 129883408346 |