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 | 1 |
| 2 | 2 |
| 3 | 6 |
| 4 | 19 |
| 5 | 63 |
| 6 | 216 |
| 7 | 756 |
| 8 | 2684 |
| 9 | 9638 |
| 10 | 34930 |
| 11 | 127560 |
| 12 | 468837 |
| 13 | 1732702 |
| 14 | 6434322 |
| 15 | 23993874 |
| 16 | 89805691 |
| 17 | 337237337 |
| 18 | 1270123530 |
| 19 | 4796310672 |
| 20 | 18155586993 |
| 21 | 68874803609 |
| 22 | 261803388854 |
| 23 | 996971935098 |
| 24 | 3802944302442 |
| 25 | 14528816598358 |