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 | 9 |
| 4 | 40 |
| 5 | 202 |
| 6 | 1068 |
| 7 | 5884 |
| 8 | 33356 |
| 9 | 193365 |
| 10 | 1140940 |
| 11 | 6829601 |
| 12 | 41372238 |
| 13 | 253156085 |
| 14 | 1562416632 |
| 15 | 9714660195 |
| 16 | 60795387840 |
| 17 | 382639224327 |
| 18 | 2420498032350 |
| 19 | 15380899180204 |
| 20 | 98134455984896 |
| 21 | 628425763698123 |
| 22 | 4037685422823604 |
| 23 | 26021345223509038 |
| 24 | 168164609160791154 |