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 | 0 |
| 2 | 1 |
| 3 | 1 |
| 4 | 3 |
| 5 | 8 |
| 6 | 22 |
| 7 | 64 |
| 8 | 189 |
| 9 | 577 |
| 10 | 1788 |
| 11 | 5642 |
| 12 | 18016 |
| 13 | 58213 |
| 14 | 189792 |
| 15 | 623913 |
| 16 | 2065219 |
| 17 | 6878429 |
| 18 | 23032917 |
| 19 | 77500237 |
| 20 | 261892491 |
| 21 | 888439320 |
| 22 | 3024510467 |
| 23 | 10329241959 |
| 24 | 35379140285 |
| 25 | 121502993735 |
| 26 | 418306868672 |
| 27 | 1443409882944 |
| 28 | 4991122973019 |
| 29 | 17292424070839 |
| 30 | 60021140494647 |
| 31 | 208684858267921 |