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 | 4 |
| 4 | 11 |
| 5 | 51 |
| 6 | 177 |
| 7 | 876 |
| 8 | 3965 |
| 9 | 20782 |
| 10 | 114462 |
| 11 | 678568 |
| 12 | 4160919 |
| 13 | 27640938 |
| 14 | 190402900 |
| 15 | 1378295071 |
| 16 | 10437144322 |
| 17 | 82285618466 |
| 18 | 671415306221 |
| 19 | 5676395537455 |