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 | 0 |
| 2 | 1 |
| 3 | 1 |
| 4 | 6 |
| 5 | 16 |
| 6 | 73 |
| 7 | 298 |
| 8 | 1453 |
| 9 | 7366 |
| 10 | 40689 |
| 11 | 238258 |
| 12 | 1483306 |
| 13 | 9746839 |
| 14 | 67415262 |
| 15 | 489048716 |
| 16 | 3710659737 |
| 17 | 29372630485 |
| 18 | 242021348787 |
| 19 | 2071598497189 |
| 20 | 18386889241210 |
| 21 | 168944811545046 |
| 22 | 1604584556714162 |
| 23 | 15731291424746912 |
| 24 | 159001720653174800 |
| 25 | 1654891767547439393 |