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 | 1 |
| 2 | 2 |
| 3 | 4 |
| 4 | 13 |
| 5 | 59 |
| 6 | 333 |
| 7 | 2233 |
| 8 | 17226 |
| 9 | 150104 |
| 10 | 1458150 |
| 11 | 15623032 |
| 12 | 183012660 |
| 13 | 2326875240 |
| 14 | 31911431854 |
| 15 | 469553925839 |
| 16 | 7378704548889 |
| 17 | 123329776031415 |
| 18 | 2184698889699347 |
| 19 | 40885079221516336 |
| 20 | 806020133224179177 |