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 | 2 |
| 3 | 5 |
| 4 | 15 |
| 5 | 52 |
| 6 | 203 |
| 7 | 877 |
| 8 | 4139 |
| 9 | 21137 |
| 10 | 115874 |
| 11 | 677623 |
| 12 | 4204927 |
| 13 | 27565188 |
| 14 | 190168577 |
| 15 | 1376119903 |
| 16 | 10414950785 |
| 17 | 82230347149 |
| 18 | 675762947626 |
| 19 | 5768465148493 |
| 20 | 51054457464731 |
| 21 | 467728049807348 |
| 22 | 4428770289719931 |
| 23 | 43281554035140829 |
| 24 | 436015324638219779 |