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 | 214 |
| 7 | 738 |
| 8 | 2571 |
| 9 | 9020 |
| 10 | 31806 |
| 11 | 112572 |
| 12 | 399548 |
| 13 | 1421145 |
| 14 | 5063254 |
| 15 | 18062902 |
| 16 | 64505148 |
| 17 | 230547424 |
| 18 | 824547052 |
| 19 | 2950565215 |
| 20 | 10562978104 |