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 | 3 |
| 4 | 7 |
| 5 | 25 |
| 6 | 106 |
| 7 | 434 |
| 8 | 2045 |
| 9 | 10707 |
| 10 | 57781 |
| 11 | 338195 |
| 12 | 2115664 |
| 13 | 13796952 |
| 14 | 95394573 |
| 15 | 692462671 |
| 16 | 5235101739 |
| 17 | 41436754261 |
| 18 | 341177640610 |
| 19 | 2915100624274 |
| 20 | 25866987547865 |
| 21 | 237448494222575 |
| 22 | 2252995117706961 |
| 23 | 22078799199129799 |
| 24 | 222971522853648704 |
| 25 | 2319210969809731600 |