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 | 0 |
| 1 | 1 |
| 2 | 4 |
| 3 | 15 |
| 4 | 52 |
| 5 | 175 |
| 6 | 571 |
| 7 | 1838 |
| 8 | 5834 |
| 9 | 18363 |
| 10 | 57372 |
| 11 | 178271 |
| 12 | 551344 |
| 13 | 1698782 |
| 14 | 5217266 |
| 15 | 15979465 |
| 16 | 48825416 |
| 17 | 148877730 |
| 18 | 453124341 |
| 19 | 1376890744 |
| 20 | 4177819301 |
| 21 | 12659943750 |
| 22 | 38317731349 |
| 23 | 115851225052 |
| 24 | 349924919167 |